Articles de revues : « SYNTHESIS, BIOMATERIAL, PEPTIDE, CARBOHYDRATE »

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Wartchow, Charles A., Peng Wang, Mark D. Bednarski et Matthew R. Callstrom. « Carbohydrate Protease Conjugates : Stabilized Proteases for Peptide Synthesis ». Journal of Organic Chemistry 60, n^o 7 (avril 1995) : 2216–26. http://dx.doi.org/10.1021/jo00112a049.

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Hossain, Farzana, Shruthi Kandalai, Xiaozhuang Zhou, Nan Zhang et Qingfei Zheng. « Chemical and Synthetic Biology Approaches for Cancer Vaccine Development ». Molecules 27, n^o 20 (16 octobre 2022) : 6933. http://dx.doi.org/10.3390/molecules27206933.

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Cancer vaccines have been considered promising therapeutic strategies and are often constructed from whole cells, attenuated pathogens, carbohydrates, peptides, nucleic acids, etc. However, the use of whole organisms or pathogens can elicit unwanted immune responses arising from unforeseen reactions to the vaccine components. On the other hand, synthetic vaccines, which contain antigens that are conjugated, often with carrier proteins, can overcome these issues. Therefore, in this review we have highlighted the synthetic approaches and discussed several bioconjugation strategies for developing antigen-based cancer vaccines. In addition, the major synthetic biology approaches that were used to develop genetically modified cancer vaccines and their progress in clinical research are summarized here. Furthermore, to boost the immune responses of any vaccines, the addition of suitable adjuvants and a proper delivery system are essential. Hence, this review also mentions the synthesis of adjuvants and utilization of biomaterial scaffolds, which may facilitate the design of future cancer vaccines.

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Herzner, Holger, Tanja Reipen, Michael Schultz et Horst Kunz. « Synthesis of Glycopeptides Containing Carbohydrate and Peptide Recognition Motifs ». Chemical Reviews 100, n^o 12 (décembre 2000) : 4495–538. http://dx.doi.org/10.1021/cr990308c.

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Badhe, Ravindra, Pradeep Kumar, Yahya Choonara, Thashree Marimuthu, Lisa du Toit, Divya Bijukumar, Dharmesh Chejara, Mostafa Mabrouk et Viness Pillay. « Customized Peptide Biomaterial Synthesis via an Environment-Reliant Auto-Programmer Stigmergic Approach ». Materials 11, n^o 4 (16 avril 2018) : 609. http://dx.doi.org/10.3390/ma11040609.

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Bini, Davide, Laura Russo, Chiara Battocchio, Antonino Natalello, Giovanni Polzonetti, Silvia Maria Doglia, Francesco Nicotra et Laura Cipolla. « Dendron Synthesis and Carbohydrate Immobilization on a Biomaterial Surface by a Double-Click Reaction ». Organic Letters 16, n^o 5 (19 février 2014) : 1298–301. http://dx.doi.org/10.1021/ol403476z.

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Racheva, M., O. Romero, K. K. Julich-Gruner, A. S. Ulrich, C. Wischke et A. Lendlein. « Purity of mushroom tyrosinase as a biocatalyst for biomaterial synthesis affects the stability of therapeutic peptides ». MRS Proceedings 1718 (2015) : 85–90. http://dx.doi.org/10.1557/opl.2015.260.

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ABSTRACTThe formation of injectable implants in the presence of cells or solutes has previously been conceptualized to be based on the selectivity of bioorthogonal chemical reactions. As an alternative approach, hydrogel network synthesis by enzymatic reactions with a typically high inherent substrate specificity and low toxicity have been repeatedly proposed, e.g. using commercial mushroom tyrosinase (MTyr), which specifically catalyzes phenol oxidation. In this study, it should be explored whether MTyr is compatible with therapeutic peptides that may be delivered from such hydrogels in the future. Based on the specificity of MTyr to phenol residues, no modification of peptides lacking the amino acid tyrosine would be expected. One example of such peptides is gramicidin S (GS), a potent antimicrobial peptide. However, when GS was incubated with commercial MTyr, peptide degradation occurred as observed by HPLC analysis. Several fragments of the peptide were detected by MALDI-TOF. Contamination of MTyr with peptidases was proven as the source of undesired peptide cleavage, which needs to be considered when preparing enzymatically crosslinked hydrogels for biomedical applications.

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Herzner, Holger, Tanja Reipen, Michael Schultz et Horst Kunz. « ChemInform Abstract : Synthesis of Glycopeptides Containing Carbohydrate and Peptide Recognition Motifs ». ChemInform 32, n^o 9 (27 février 2001) : no. http://dx.doi.org/10.1002/chin.200109270.

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Fernandes, Rafaella F., Giordano T. Paganoto et Marcia L. A. Temperini. « Non-traditional intrinsic luminescence from non-conjugated polymer dots : designing a hybrid biomaterial ». Polymer Chemistry 12, n^o 43 (2021) : 6319–28. http://dx.doi.org/10.1039/d1py01104a.

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Herein, an eco-friendly and facile synthesis of nitrogen-containing non-conjugated polymer dots (NCPD) with optimal blue emission is reported from the biopolymer β-glucan with a peptide–polysaccharide linkage (namely NH2-β-glucan).

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Wu, Fang-Yi, et Hsin-Chieh Lin. « Synthesis, Self-Assembly, and Cell Responses of Aromatic IKVAV Peptide Amphiphiles ». Molecules 27, n^o 13 (27 juin 2022) : 4115. http://dx.doi.org/10.3390/molecules27134115.

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Synthetic bioactive aromatic peptide amphiphiles have been recognized as key elements of emerging biomedical strategies due to their biocompatibility, design flexibility, and functionality. Inspired by natural proteins, we synthesized two supramolecular materials of phenyl-capped Ile-Lys-Val-Ala-Val (Ben-IKVAV) and perfluorophenyl-capped Ile-Lys-Val-Ala-Val (PFB-IKVAV). We employed UV-vis absorption, fluorescence, circular dichroism, and Fourier-transform infrared spectroscopy to examine the driving force in the self-assembly of the newly discovered materials. It was found that both compounds exhibited ordered π-π interactions and secondary structures, especially PFB-IKVAV. The cytotoxicity of human mesenchymal stem cells (hMSCs) and cell differentiation studies was also performed. In addition, the immunofluorescent staining for neuronal-specific markers of MAP2 was 4.6 times (neural induction medium in the presence of PFB-IKVAV) that of the neural induction medium (control) on day 7. From analyzing the expression of neuronal-specific markers in hMSCs, it can be concluded that PFB-IKVAV may be a potential supramolecular biomaterial for biomedical applications.

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Zhong, Wei, Mariusz Skwarczynski, Yoshio Fujita, Pavla Simerska, Michael F. Good et Istvan Toth. « Design and Synthesis of Lipopeptide - Carbohydrate Assembled Multivalent Vaccine Candidates Using Native Chemical Ligation ». Australian Journal of Chemistry 62, n^o 9 (2009) : 993. http://dx.doi.org/10.1071/ch09065.

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Development of a synthetic vaccine against group A streptococcal infection is increasingly paramount due to the induction of autoimmunity by the main virulent factor – M protein. Peptide vaccines, however, are generally poorly immunogenic, necessitating administration with carriers and adjuvants. One of the promising approaches to deliver antigenic peptides is to assemble peptides on a suitable template which directs the attached peptides to form a well defined tertiary structure. For self-adjuvanting human vaccines, the conjugation of immunostimulatory lipids has been demonstrated as a potentially safe method. This study describes the design and optimized synthesis of two lipopeptide conjugated carbohydrate templates and the assembling of peptide antigens. These lipopeptide–carbohydrate assembled multivalent vaccine candidates were obtained in high yield and purity when native chemical ligation was applied. Circular dichroism studies indicated that the template-assembled peptides form four α-helix bundles. The developed technique extends the use of carbohydrate templates and lipopeptide conjugates for producing self-adjuvanting and topology-controlled vaccine candidates.

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Opatz, Till, Christopher Kallus, Tobias Wunberg et Horst Kunz. « Combinatorial synthesis of amino acid- and peptide-carbohydrate conjugates on solid phase ». Tetrahedron 60, n^o 39 (septembre 2004) : 8613–26. http://dx.doi.org/10.1016/j.tet.2004.05.101.

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Matsubara, Teruhiko. « Potential of Peptides as Inhibitors and Mimotopes : Selection of Carbohydrate-Mimetic Peptides from Phage Display Libraries ». Journal of Nucleic Acids 2012 (2012) : 1–15. http://dx.doi.org/10.1155/2012/740982.

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Glycoconjugates play various roles in biological processes. In particular, oligosaccharides on the surface of animal cells are involved in virus infection and cell-cell communication. Inhibitors of carbohydrate-protein interactions are potential antiviral drugs. Several anti-influenza drugs such as oseltamivir and zanamivir are derivatives of sialic acid, which inhibits neuraminidase. However, it is very difficult to prepare a diverse range of sugar derivatives by chemical synthesis or by the isolation of natural products. In addition, the pathogenic capsular polysaccharides of bacteria are carbohydrate antigens, for which a safe and efficacious method of vaccination is required. Phage-display technology has been improved to enable the identification of peptides that bind to carbohydrate-binding proteins, such as lectins and antibodies, from a large repertoire of peptide sequences. These peptides are known as “carbohydrate-mimetic peptides (CMPs)” because they mimic carbohydrate structures. Compared to carbohydrate derivatives, it is easy to prepare mono- and multivalent peptides and then to modify them to create various derivatives. Such mimetic peptides are available as peptide inhibitors of carbohydrate-protein interactions and peptide mimotopes that are conjugated with adjuvant for vaccination.

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Depezay, J. C. « ChemInform Abstract : Synthesis of Enantiopure Azasugars from D-mannitol : Carbohydrate and Peptide Mimics ». ChemInform 30, n^o 22 (15 juin 2010) : no. http://dx.doi.org/10.1002/chin.199922260.

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Pawar, Nitin J., Navdeep S. Sidhu, George M. Sheldrick, Dilip D. Dhavale et Ulf Diederichsen. « Molecular architecture with carbohydrate functionalized β-peptides adopting 314-helical conformation ». Beilstein Journal of Organic Chemistry 10 (28 avril 2014) : 948–55. http://dx.doi.org/10.3762/bjoc.10.93.

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Carbohydrate recognition is essential in cellular interactions and biological processes. It is characterized by structural diversity, multivalency and cooperative effects. To evaluate carbohydrate interaction and recognition, the structurally defined attachment of sugar units to a rigid template is highly desired. β-Peptide helices offer conformationally stable templates for the linear presentation of sugar units in defined distances. The synthesis and β-peptide incorporation of sugar-β-amino acids are described providing the saccharide units as amino acid side chain. The respective sugar-β-amino acids are accessible by Michael addition of ammonia to sugar units derivatized as α,β-unsaturated esters. Three sugar units were incorporated in β-peptide oligomers varying the sugar (glucose, galactose, xylose) and sugar protecting groups. The influence of sugar units and the configuration of sugar-β-amino acids on β-peptide secondary structure were investigated by CD spectroscopy.

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Scheibe, Christian, et Oliver Seitz. « PNA–sugar conjugates as tools for the spatial screening of carbohydrate–lectin interactions ». Pure and Applied Chemistry 84, n^o 1 (8 décembre 2011) : 77–85. http://dx.doi.org/10.1351/pac-con-11-08-07.

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Multivalent carbohydrate–lectin interactions are essential for a multitude of biological recognition events. Much effort has been spent in the synthesis of potent multivalent scaffolds in order to mimic or inhibit biological carbohydrate–protein interactions. However, the defined spatial presentation of carbohydrates remained a challenging task. Peptide nucleic acid (PNA)- and DNA-based double helices are useful scaffolds that enable the controlled display of carbohydrate ligands in a modular approach. The hybridization of PNA-sugar conjugates with complementary DNA strands provides multivalent complexes with defined spatial presentation of carbohydrates, which facilitates the spatial screening of carbohydrate–lectin interactions with Ångström-scale precision.

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Jiang, Rui-Jian, Bo Yang, Dong Yi, Fen Wang, Bin Han, Yu-Lin Zhao, Xia-Li Liao, Jian Yang et Chuan-Zhu Gao. « Synthesis and characterization of a series of novel amino β-cyclodextrin-conjugated poly(ε-lysine) derivatives ». Journal of Polymer Engineering 34, n^o 2 (1 avril 2014) : 133–39. http://dx.doi.org/10.1515/polyeng-2013-0194.

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Abstract Soluble poly(ε-lysine)s bearing β-cyclodextrin (β-CD) moieties were prepared by three amino β-CD derivatives and N-succinylated poly(ε-lysine), in which the poly(ε-lysine) and amino β-CD derivatives were bonded covalently to the end carboxyl groups of succinic acid by peptide bonds. 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDCI) and N-hydroxysuccinimide (NHS) were chosen to assist the reaction. The three poly(ε-lysine) derivatives were characterized by 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR). The synthesis process is simple, feasible and has strong practicability. The target polymers can serve as new polymer biomaterial for use in the biotechnology area.

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Waynant, Kristopher V., et Moubani Chakraborty. « Outside-In Strategy for Peptide-Based Methacrylate and Methacrylamide Zwitterionic Cross-Linkers ». Synlett 33, n^o 07 (28 janvier 2022) : 669–73. http://dx.doi.org/10.1055/a-1754-2437.

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AbstractPolyampholyte hydrogels have shown promise as functional biomaterial platforms with resistance to nonspecific protein adsorption (nonbiofouling). Yet there are few zwitterionic cross-linkers available to complement these materials and to provide an extended charge density throughout the 3D network. The recent development of peptide-based zwitterionic cross-linkers has shown merit. Indeed, the use of functionalizable amino acids permits the synthesis of a series of peptide-based zwitterionic methacrylate and methacrylamide cross-linkers. Methacrylate additions prior to peptide coupling provide an outside-in strategy when using natural l-serine or l-lysine as substrates to produce a series of methacrylate and methacrylamide combinations, expanding the library of peptide-based cross-linkers. Here, we describe the preparation of such dipeptide combinations as Ser-Lys, Lys-Ser, and Lys-Lys in zwitterionic bis(methacrylate/methacrylamide) cross-linkers. To highlight the utility of this method and its potential to increase the distance between zwitterionic components, syntheses of the tripeptide Lys-Gly-Lys dimethacrylamide and Ser-Gly-Ser dimethacrylate are reported.

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Leighton, B., et E. A. Foot. « The role of the sensory peptide calcitonin-gene-related peptide(s) in skeletal muscle carbohydrate metabolism : effects of capsaicin and resiniferatoxin ». Biochemical Journal 307, n^o 3 (1 mai 1995) : 707–12. http://dx.doi.org/10.1042/bj3070707.

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1. The content of calcitonin-gene-related-peptide-like immunoreactivity (CGRP-LI) in various rat muscles was measured. Starvation for 24 h did not affect the content of CGRP-LI in these muscles, except for a decreased level in the starved-rat diaphragm. Higher contents of CGRP-LI were observed in well-vascularized muscles. 2. Capsaicin (at 1, 10 and 100 microM) inhibited insulin-stimulated rates of glycogen synthesis in isolated stripped incubated soleus muscle preparations by a mechanism independent of catecholamine release, since the effects of capsaicin were not altered by the beta-adrenoreceptor antagonist DL-propranolol. 3. Resiniferatoxin (10 nM), which is a potent capsaicin agonist, also significantly inhibited the insulin-stimulated rate of glycogen synthesis. Furthermore, the concentration of resiniferatoxin required to inhibit glycogen synthesis was 100 times less than the concentration of capsaicin needed for the same effect. 4. Capsaicin (10 microM) decreased the content of CGRP-LI in isolated stripped incubated soleus muscle preparations by about 40%. 5. Neonatal treatment of rats with capsaicin, which causes de-afferentation of some sensory nerves such, we hypothesize, that CGRP can no longer be released to counteract the effects of insulin in vivo, caused increased rates of glycogen synthesis and increased glycogen content in stripped soleus muscle preparations in vitro when muscles were isolated from the adult rats. 6. These findings support the hypothesis that capsaicin and resiniferatoxin elicit an excitatory response on sensory nerves in skeletal muscle in vitro to cause the efferent release of CGRP. Consequently, CGRP is delivered to skeletal muscle fibres to inhibit insulin-stimulated glycogen synthesis. The role of CGRP in recovery of blood glucose levels during hypoglycaemia is discussed.

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Güell, Imma, Rafael Ferre, Kasper Kildegaard Sørensen, Esther Badosa, Iteng Ng-Choi, Emilio Montesinos, Eduard Bardají, Lidia Feliu, Knud J. Jensen et Marta Planas. « Multivalent display of the antimicrobial peptides BP100 and BP143 ». Beilstein Journal of Organic Chemistry 8 (3 décembre 2012) : 2106–17. http://dx.doi.org/10.3762/bjoc.8.237.

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Carbohydrates are considered as promising templates for the display of multiple copies of antimicrobial peptides. Herein, we describe the design and synthesis of chimeric structures containing two or four copies of the antimicrobial peptides KKLFKKILKYL-NH2 (BP100) and KKLfKKILKYL-NH2 (BP143) attached to the carbohydrate template cyclodithioerythritol (cDTE) or α-D-galactopyranoside (Galp). The synthesis involved the preparation of the corresponding peptide aldehyde followed by coupling to an aminooxy-functionalized carbohydrate template. After purification, the multivalent display systems were obtained in high purities (90–98%) and in good yields (42–64%). These compounds were tested against plant and human pathogenic bacteria and screened for their cytotoxicity on eukaryotic cells. They showed lower MIC values than the parent peptides against the bacteria analyzed. In particular, the carbopeptides derived from cDTE and Galp, which contained two or four copies of BP100, respectively, were 2- to 8-fold more active than the monomeric peptide against the phytopathogenic bacteria. These results suggest that preassembling antimicrobial peptides to multimeric structures is not always associated with a significant improvement of the activity. In contrast, the carbopeptides synthesized were active against human red blood cells pointing out that peptide preassembly is critical for the hemolytic activity. Notably, peptide preassembly resulted in an enhanced bactericidal effect.

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Forget, D., D. Boturyn, O. Renaudet, E. Defrancq et P. Dumy. « Highly Efficient Synthesis of Peptide- and Carbohydrate-Oligonucleotide Conjugates Using Chemoselective Oxime and Thiazolidine Formation ». Nucleosides, Nucleotides and Nucleic Acids 22, n^o 5-8 (octobre 2003) : 1427–29. http://dx.doi.org/10.1081/ncn-120023001.

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Kihlberg, Jan, et Mikael Elofsson. « Solid-Phase Synthesis of Glycopeptides : Immunological Studies with T Cell Stimulating Glycopeptides ». Current Medicinal Chemistry 4, n^o 2 (avril 1997) : 85–116. http://dx.doi.org/10.2174/0929867304666220309204820.

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Stepwise solid-phase synthesis using glycosylated amino acids as puilding blocks has been shown to be the most general and efficient approach for preparation of glycopeptides. The a-amino group of the glycosylated amino acids should be protected with the fluoren-9-ylmethoxy carbonyl (Fmoc) group whereas acetyl groups, or acid labile protective groups, are suitable for the carbohydrate hydroxyl groups. Due to the recent rapid development of Fmoc solid-phase glycopeptide synthesis glycopeptides are increasingly being made available for investigations in biological sciences, such as studies of the cellular immune response to glycopeptides. These studies have established that glycopeptides are bound well by both class I and . II MHC molecules and elicit a carbohydrate specific T cell response after immunization, provided that the position for the glycan is chosen carefully in the centre of the peptide. Such a location most likely allows contacts between carbohydrate and the CDR3s of the T cell receptor. Investigations using viral glycoproteins suggest that the large N-linked glycans influence the T cell response to glycoproteins, but that this does not involve specific interactions between the glycan and the T cell. Furthermore, viruses seem to exploit mutations which introduce or delete N-linked glycans to escape from attack by T cells. In contrast, studies have revealed that the smaller 0-linked carbohydrates found on collagen or mucins are able to elicit a carbohydrate specific T cell response. Altogether, these immunological studies have suggested novel applications in medicine, including generation of a cellular immune response to carbohydrate antigens found on pathogens or tumour cells, and induction of tolerance in autoimmune rheumatoid arthritis.

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Sršan, Laura, et Thomas Ziegler. « Synthesis of new asparagine-based glycopeptides for future scanning tunneling microscopy investigations ». Beilstein Journal of Organic Chemistry 16 (30 avril 2020) : 888–94. http://dx.doi.org/10.3762/bjoc.16.80.

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For investigations on the biological functions of oligosaccharides and peptidomimetics, new asparagine-based mono- and disaccharides containing glycopeptides were prepared in solution. The applicability of two common peptide coupling reagents, using an orthogonal Fmoc/t-Bu strategy along with acetyl protecting groups for the carbohydrate moiety, was studied. Thus, the prepared libraries of glycopeptides were designed as model systems of cell surfaces for future investigations by combined preparative mass spectroscopy and scanning tunneling microscopy (STM) using soft-landing electrospray beam deposition (ES-IBD), on metal surfaces.

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Johnson, Margaret A., Adewale A. Eniade et B. Mario Pinto. « Rational design and synthesis of peptide ligands for an anti-Carbohydrate antibody and Their immunochemical characterization ». Bioorganic & ; Medicinal Chemistry 11, n^o 5 (mars 2003) : 781–88. http://dx.doi.org/10.1016/s0968-0896(02)00449-2.

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Rivera, Daniel G., Karell Pérez-Labrada, Liudmila Lambert, Simon Dörner, Bernhard Westermann et Ludger A. Wessjohann. « Carbohydrate–steroid conjugation by Ugi reaction : one-pot synthesis of triple sugar/pseudo-peptide/spirostane hybrids ». Carbohydrate Research 359 (octobre 2012) : 102–10. http://dx.doi.org/10.1016/j.carres.2012.05.003.

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George, Shaji K., Björn Holm, Celso A. Reis, Tilo Schwientek, Henrik Clausen et Jan Kihlberg. « Chemoenzymatic synthesis of derivatives of a T-cell-stimulating peptide which carry tumor-associated carbohydrate antigens ». Journal of the Chemical Society, Perkin Transactions 1, n^o 8 (2001) : 880–85. http://dx.doi.org/10.1039/b009567m.

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Duggan, Peter J., et Daniel A. Offermann. « The Preparation of Solid-Supported Peptide Boronic Acids Derived from 4-Borono-L-phenylalanine and their Affinity for Alizarin ». Australian Journal of Chemistry 60, n^o 11 (2007) : 829. http://dx.doi.org/10.1071/ch07143.

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A library of solid-supported pentapeptide diboronic acids, a ‘lysine series’ and an ‘arginine series’, has been efficiently prepared using N-Fmoc-4-pinacolatoborono-l-phenylalanine and standard solid phase peptide synthesis methods. A technique for measuring the affinity of the chromophoric diol, alizarin, to the solid-supported peptide boronic acids has been developed. Considerable variation in alizarin binding strengths, both within and between arginine and lysine series was observed, with association constants in the range 200–1100 M–1 being recorded. The selective binding characteristics of these boronic acid–peptide hybrids suggest their potential use in carbohydrate sensors and cell-specific diagnostics and therapeutics.

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Timmer, Mattie S. M., Steven H. L. Verhelst, Gijsbert M. Grotenbreg, Mark Overhand et Herman S. Overkleeft. « Carbohydrates as versatile platforms in the construction of small compound libraries ». Pure and Applied Chemistry 77, n^o 7 (1 janvier 2005) : 1173–81. http://dx.doi.org/10.1351/pac200577071173.

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This paper presents our recent results concerning the use of carbohydrates as cheap, chiral, and enantiopure starting materials in the construction of a variety of densely functionalized molecules. The compatibility of ring-closing metathesis with standard carbohydrate chemistry is demonstrated in the synthesis of new stereoisomers of deoxystreptamine and neamine–important building blocks for the generation of synthetic aminoglycosides with potential antibacterial activity. Ring-closing metathesis is also a key step in the rapid synthesis of new indolizidines and quinolizidines, and in a new solid-phase assisted carbohydrate-based combinatorial scaffold strategy. Further, some of our latest results in the conformational analysis of sugar amino acid-based peptide mimetics and in the development of a novel Ugi-type three-component reaction of sugar-derived azido-aldehydes are discussed.

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Lin, Feng, Mohammed Akhter Hossain, Stephanie Post, Galina Karashchuk, Marc Tatar, Pierre De Meyts et John D. Wade. « Total Solid-Phase Synthesis of Biologically Active Drosophila Insulin-Like Peptide 2 (DILP2) ». Australian Journal of Chemistry 70, n^o 2 (2017) : 208. http://dx.doi.org/10.1071/ch16626.

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In the fruit fly Drosophila melanogaster, there are eight insulin-like peptides (DILPs) with DILPs 1–7 interacting with a sole insulin-like receptor tyrosine kinase (DInR) while DILP8 interacts with a single G protein-coupled receptor (GPCR), Lgr3. Loss-of-function dilp mutation studies show that the neuropeptide DILP2 has a key role in carbohydrate and lipid metabolism as well as longevity and reproduction. A better understanding of the processes whereby DILP2 mediates its specific actions is required. Consequently we undertook to prepare DILP2 as part of a larger, detailed structure–function relationship study. Use of our well established insulin-like peptide synthesis protocol that entails separate solid-phase assembly of each of the A- and B-chains with selective cysteine S-protection followed by sequential S-deprotection and simultaneous disulfide bond formation produced DILP2 in good overall yield and high purity. The synthetic DILP2 was shown to induce significant DInR phosphorylation and downstream signalling, with it being more potent than human insulin. This peptide will be a valuable tool to provide further insights into its binding to the insulin receptor, the subsequent cell signalling, and role in insect metabolism.

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Tian, Xizhe, Jaeyoung Pai, Kyung-Hwa Baek, Sung-Kyun Ko et Injae Shin. « Fluorophore-labeled, Peptide-based Glycoclusters : Synthesis, Binding Properties for Lectins, and Detection of Carbohydrate-Binding Proteins in Cells ». Chemistry - An Asian Journal 6, n^o 8 (1 juin 2011) : 2107–13. http://dx.doi.org/10.1002/asia.201100319.

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Denning, Gerene M., Kevin G. Leidal, Valerie A. Holst, Shankar S. Iyer, Doran W. Pearson, Joshua R. Clark, William M. Nauseef et Robert A. Clark. « Calreticulin Biosynthesis and Processing in Human Myeloid Cells : Demonstration of Signal Peptide Cleavage and N-Glycosylation ». Blood 90, n^o 1 (1 juillet 1997) : 372–81. http://dx.doi.org/10.1182/blood.v90.1.372.

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Abstract Calreticulin is a soluble endoplasmic reticulum protein comprising the major storage reservoir for inositol trisphosphate-releasable calcium. Although its highly conserved primary structure and a wide range of functions have been well described, less attention has been paid to its biosynthesis, particularly in human tissues. We report analyses of synthesis, proteolytic processing and glycosylation of human calreticulin. In both HL-60 and PLB-985 myeloid cell lines calreticulin was immunoprecipitated as a single 60-kD species without evidence of precursor forms. However, in vitro cell-free synthesis produced a 62-kD primary translation product, which in the presence of microsomal membranes, was processed by cotranslational signal peptide cleavage to a 60-kD species that comigrated with mature calreticulin produced in myeloid cells. Neither tunicamycin treatment of the cells nor endoglycosidase digestion of calreticulin resulted in any forms other than the 60-kD protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, suggesting that the potential site for N-glycosylation at asparagine-327 was unmodified. However, oxidative derivatization of carbohydrate components with digoxigenin showed that human calreticulin produced in either HL-60 cells or Sf9 insect cells is glycosylated, indicating that glycosylated and nonglycosylated human calreticulin have indistinguishable electrophoretic mobilities. Direct measurement by phenol-H2SO4 confirmed the presence of carbohydrate on recombinant human calreticulin. These data show that human myeloid calreticulin undergoes cotranslational signal peptide cleavage and posttranslational N-linked glycosylation. Although glycosylation of calreticulin has been shown in rat liver and bovine liver and brain, it has been reported to be lacking in other tissues including human lymphocytes.

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Denning, Gerene M., Kevin G. Leidal, Valerie A. Holst, Shankar S. Iyer, Doran W. Pearson, Joshua R. Clark, William M. Nauseef et Robert A. Clark. « Calreticulin Biosynthesis and Processing in Human Myeloid Cells : Demonstration of Signal Peptide Cleavage and N-Glycosylation ». Blood 90, n^o 1 (1 juillet 1997) : 372–81. http://dx.doi.org/10.1182/blood.v90.1.372.372_372_381.

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Calreticulin is a soluble endoplasmic reticulum protein comprising the major storage reservoir for inositol trisphosphate-releasable calcium. Although its highly conserved primary structure and a wide range of functions have been well described, less attention has been paid to its biosynthesis, particularly in human tissues. We report analyses of synthesis, proteolytic processing and glycosylation of human calreticulin. In both HL-60 and PLB-985 myeloid cell lines calreticulin was immunoprecipitated as a single 60-kD species without evidence of precursor forms. However, in vitro cell-free synthesis produced a 62-kD primary translation product, which in the presence of microsomal membranes, was processed by cotranslational signal peptide cleavage to a 60-kD species that comigrated with mature calreticulin produced in myeloid cells. Neither tunicamycin treatment of the cells nor endoglycosidase digestion of calreticulin resulted in any forms other than the 60-kD protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, suggesting that the potential site for N-glycosylation at asparagine-327 was unmodified. However, oxidative derivatization of carbohydrate components with digoxigenin showed that human calreticulin produced in either HL-60 cells or Sf9 insect cells is glycosylated, indicating that glycosylated and nonglycosylated human calreticulin have indistinguishable electrophoretic mobilities. Direct measurement by phenol-H2SO4 confirmed the presence of carbohydrate on recombinant human calreticulin. These data show that human myeloid calreticulin undergoes cotranslational signal peptide cleavage and posttranslational N-linked glycosylation. Although glycosylation of calreticulin has been shown in rat liver and bovine liver and brain, it has been reported to be lacking in other tissues including human lymphocytes.

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Dondoni, Alessandro. « Selected Research Topics of the Dondoni Group over the Last Two Decades (2000–2020) ». Synlett 31, n^o 14 (7 mai 2020) : 1361–71. http://dx.doi.org/10.1055/s-0040-1707107.

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From a selection of research topics carried out in our laboratory during the last twenty years it becomes apparent that our main target was the discovery of new or improved synthetic methods together with new properties. Our efforts were made with the aim of being of some utility to other fields of research, with particular emphasis to glycobiology and heterocyle-based bioorganic chemistry. We performed new chemistry mainly in the field of carbohydrate manipulations taking as a primary rule the simplicity and efficiency manners. Toward this end, modern synthetic tools and approaches were employed such as heterocyle-based transformations, multicomponent reactions, organocatalysis, click azide–alkyne cycloadditions, reactions in ionic liquids, click photoinduced thiol-ene coupling, and click sulfur–fluoride exchange chemistry. With these potent methodologies in hand, the syntheses of carbohydrate containing amino acids up to proteins glycosylation were performed.1 Heterocyclic Glycoconjugates and Amino Acids2 Triazole-Linked Oligonucleotides: Application of Click CuAAC3 Non-Natural Glycosyl Amino Acids4 Non-Natural Oligosaccharides5 Calixarene-Based Glycoclusters6 Carbohydrate-Based Building Blocks7 Homoazasugars and Aza-C-disaccharides8 Synthesis of Glycodendrimers9 Peptide and Protein Glycoconjugates10 Conclusions

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Nikolaeva, Tatiana N., Tatiana N. Kozhevnikova, Elena I. Vostrova, Olga Yu Sosnovskaya, Ekaterina A. Grigorieva, Vyacheslav V. Kozlov, Alexei V. Vostrov et al. « Comparative assessment of the intestinal microbiota, lipid metabolism and morphological changes of the liver in experimental models of metabolic syndrome ». Experimental and Clinical Gastroenterology, n^o 7 (7 octobre 2022) : 158–64. http://dx.doi.org/10.31146/1682-8658-ecg-203-7-158-164.

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Metabolic syndrome (MS) is a widespread polyethiological clustering characterized by metabolic, hormonal disorders and clinical manifestations that significantly increase the risk of developing cardiovascular diseases, atherosclerosis, type II diabetes and other pathological conditions. An important role in the development of MS is assigned to the intestinal microbiota. To develop new therapeutic agents for correction of MS manifestations, it is necessary to develop adequate experimental models. In this paper, comparative studies were conducted to assess the parameters of lipid metabolism, the content of peptide hormones, morphological changes in liver tissue, and the quantitative and generic composition of the intestinal microbiota of mice. Experimental models of experimental hyperlipidemia (HL) caused by the introduction of poloxamer 407 (Pol407) and alimentary MS (a diet with fructose and the addition of cholesterol to the feed) were used. Significant increase in the levels of cholesterol, triglycerides, and low-density lipoprotein (LDL) was found in the group of mice treated with Pol407 injections. To assess the indicators of carbohydrate metabolism in blood serum, the following markers were determined: insulin, adiponectin, leptin. In the alimentary MS model a decrease in adiponectin in the blood serum, while insulin level was increased. In both experimental models, significant changes in the gut microbiota of mice were observed. They were associated with the manifestation of metabolic dysbiosis - an increase in the representation of Firmicutes (staphylococci, streptococci, enterococci) in the biomaterial, changes among representatives of both facultative (E. coli), and transient (Enterobacter bacteria) microflora. In addition, dystrophic, as well as morphological changes and signs of inflammation in the liver tissue were noted in both groups.

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Hahm, Heung Sik, Mark K. Schlegel, Mattan Hurevich, Steffen Eller, Frank Schuhmacher, Johanna Hofmann, Kevin Pagel et Peter H. Seeberger. « Automated glycan assembly using the Glyconeer 2.1 synthesizer ». Proceedings of the National Academy of Sciences 114, n^o 17 (10 avril 2017) : E3385—E3389. http://dx.doi.org/10.1073/pnas.1700141114.

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Reliable and rapid access to defined biopolymers by automated DNA and peptide synthesis has fundamentally altered biological research and medical practice. Similarly, the procurement of defined glycans is key to establishing structure–activity relationships and thereby progress in the glycosciences. Here, we describe the rapid assembly of oligosaccharides using the commercially available Glyconeer 2.1 automated glycan synthesizer, monosaccharide building blocks, and a linker-functionalized polystyrene solid support. Purification and quality-control protocols for the oligosaccharide products have been standardized. Synthetic glycans prepared in this way are useful reagents as the basis for glycan arrays, diagnostics, and carbohydrate-based vaccines.

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Ross, Günther, et Ivar Ugi. « Stereoselective syntheses of α-amino acid and peptide derivatives by the U-4CR of 5-desoxy-5-thio-D-xylopyranosylamine ». Canadian Journal of Chemistry 79, n^o 12 (1 décembre 2001) : 1934–39. http://dx.doi.org/10.1139/v01-186.

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Since 1961, the synthesis of α-amino acids derivatives by the four-component reaction of isocyanides (U-4CR) as a one-pot reaction has been developed. Only recently it was found that a variety of these α-amino acids compounds can be formed stereoselectively by the U-4CR using 1-amino-5-deoxy-5-thio-2,3,4-tri-O-isobutanoyl-β-D-xylopyranose as the amine component. The stereoselectivity inducing auxiliary 5-desoxy-5-thio-D-xylopyranosyl group of the so-formed products can be replaced selectively by hydrogen.Key words: stereoselective U-4CR, chiral amine component, amino carbohydrate, α-amino acid derivatives.

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Montero, Ana, Enrique Mann et Bernardo Herradón. « The Overman rearrangement in carbohydrate chemistry : stereoselective synthesis of functionalized 3-amino-3,6-dihydro-2H-pyrans and incorporation in peptide derivatives ». Tetrahedron Letters 46, n^o 3 (janvier 2005) : 401–5. http://dx.doi.org/10.1016/j.tetlet.2004.11.109.

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Utkina, V. A., et L. M. Stepchenko. « The effect of humic substances on carbohydrate metabolism in alloxan-induced diabetes mellitus in rats ». Theoretical and Applied Veterinary Medicine 9, n^o 2 (2021) : 96–97. http://dx.doi.org/10.32819/2021.92015.

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The article presents study results of the effect of humic nature biologically active additive «Humilid» on carbohydrate metabolism, namely on glucose, insulin and C-peptide in alloxan-induced diabetes mellitus in rats. The purpose of the experiment was to investigate how “Humilid” affects carbohydrate metabolism in rats; to study and analyze the effect of the humic nature biologically active substance «Humilid» on metabolic processes. In the work we used biochemical methods for studying the blood of experimental rats. Adult male white rats were taken for the experiment, from which four groups were formed. The experiment lasted three weeks, during which the animals from the first experimental group received daily in addition to the main feed an aqueous solution of feed additive «Humilid» at dose 5 mg / kg of body weight of the active substance, and had free access to water. Rats of the second and third groups were injected with alloxan as a single intraperitoneal injection. The rats of the third group additionally received an aqueous solution of feed additive «Humilid». It was identified that “Humilid” has an antioxidant activity, which may be one of the mechanisms of its antidiabetic action, as it is known that alloxan causes free radical damage to β-cells with weak antioxidant protection. The use of a biologically active feed additive of humic nature was found to have a hypoglycemic effect in both healthy animals as well as in rats with alloxan-induced diabetes mellitus. It was found that the use of “Humilid” in rats enhances energy processes in their bodies of experimental animals. There was a decrease in glucose content in rats from second group by 11.9% (P ≤ 0.001) compared with the control one. At the same time, the glucose content in animals from third and fourth groups was higher by 35.9% (P ≤ 0.001) and 20% (P ≤ 0.001) higher than in animals from the control one. The insulin concentration in the blood of rats from the second group was 7.4% higher (P ≤ 0.05) compared to the animals from first group. The concentration of C-peptide was within the reference values. The levels of insulin and C-peptide concentration in animals of the third and groups were lower by 47.8% (P ≤ 0.001) and 32.4% (P ≤ 0.001) and 55.5% (P ≤ 0.001) and 37.5% (P ≤ 0.001) in comparison with animals of first group. A pronounced hypoglycemic effect, which was due to an increase in the sensitivity of tissues to glucoregulatory hormones and an increase in the body’s tolerance to excessive intake of carbohydrates. The obtained results of the study indicate the regulatory effect of humic feed additive «Humilid» on key links in the regulation of carbohydrate metabolism, which is characterized by the decrease in blood glucose level due to activation of the synthesis and secretion of insulin and C-peptide.

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Kumar, K. Ganesh, Angela C. Poole, Barbara York, Julia Volaufova, Aamir Zuberi et Brenda K. Smith Richards. « Quantitative trait loci for carbohydrate and total energy intake on mouse chromosome 17 : congenic strain confirmation and candidate gene analyses (Glo1, Glp1r) ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 292, n^o 1 (janvier 2007) : R207—R216. http://dx.doi.org/10.1152/ajpregu.00491.2006.

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Quantitative trait loci (QTL) for carbohydrate ( Mnic1) and total energy ( Kcal2) intake on proximal mouse chromosome 17 were identified previously from a C57BL/6J (B6) X CAST/Ei (CAST) intercross. Here we report that a new congenic strain developed in our laboratory has confirmed this complex locus by recapitulating the original linked phenotypes: B6.CAST-17 homozygous congenic mice consumed more carbohydrate (27%) and total energy (17%) compared with littermate wild-type mice. Positional gene candidates with relevance to carbohydrate metabolism, glyoxalase I ( Glo1) and glucagon-like peptide-1 receptor ( Glp1r), were evaluated. Glo1 expression was upregulated in liver and hypothalamus of congenic mice when compared with B6 mice. Analyses of Glp1r mRNA and protein expression revealed tissue-specific strain differences in pancreas (congenic>B6) and stomach (B6>congenic). These results suggest the possibility of separate mechanisms for enhanced insulin synthesis and gastric accommodation in the presence of high carbohydrate intake and larger food volume, respectively. Sequence analysis of Glp1r found a G insert at nt position 1349, which results in earlier termination of the open reading frame, thus revealing an error in the public sequence. Consequently, the predicted length of GLP-1R is 463 aa compared with 489 aa, as previously reported. Also, we found a polymorphism in Glp1r between parental strains that alters the amino acid sequence. Variation in Glp1r could influence nutrient intake in this model through changes in the regulatory or protein coding regions of the gene. These congenic mice offer a powerful tool for investigating gene interactions in the control of food intake.

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Gyuricza, Barbara, Ágnes Szűcs, Judit P. Szabó, Viktória Arató, Zita Képes, Dániel Szücs, Dezső Szikra, György Trencsényi et Anikó Fekete. « The Synthesis and Preclinical Investigation of Lactosamine-Based Radiopharmaceuticals for the Detection of Galectin-3-Expressing Melanoma Cells ». Pharmaceutics 14, n^o 11 (18 novembre 2022) : 2504. http://dx.doi.org/10.3390/pharmaceutics14112504.

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Given that galectin-3 (Gal-3) is a β-galactoside-binding lectin promoting tumor growth and metastatis, it could be a valuable target for the treatment of Gal-3-expressing neoplasms. An aromatic group introduced to the C-3′ position of lactosamine increased its affinity for Gal-3. Herein, we aimed at developing a radiopharmaceutical for the detection of Gal-3 positive malignancies. To enhance tumor specificity, a heterodimeric radiotracer capable of binding to both Gal-3 and αvβ3 integrin was also synthetized. Arginine-glycine-asparagine (RGD) peptide is the ligand of angiogenesis- and metastasis-associated αvβ3 integrin. Following the synthesis of the chelator-conjugated (2-naphthyl)methylated lactosamine, the obtained compound was applied as a precursor for radiolabeling and was conjugated to the RGD peptide by click reaction as well. Both synthetized precursors were radiolabeled with 68Ga, resulting in high labeling yield (>97). The biological studies were carried out using B16F10 melanoma tumor-bearing C57BL6 mice. High tumor accumulation of both labeled lactosamine derivatives—detected by in vivo PET and ex vivo biodistribution studies—indicated their potential for melanoma detection. However, the heterodimer radiotracer showed high hepatic uptake, while low liver accumulation characterized chelator-conjugated lactosamine, resulting in PET images with excellent contrast. Therefore, this novel carbohydrate-based radiotracer is suitable for the highly selective determination of Gal-3-expressing melanoma cells.

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Wang, Yun, Kevin Seburn, Lawrence Bechtel, Bruce Y. Lee, Jin P. Szatkiewicz, Patsy M. Nishina et Jürgen K. Naggert. « Defective carbohydrate metabolism in mice homozygous for the tubby mutation ». Physiological Genomics 27, n^o 2 (octobre 2006) : 131–40. http://dx.doi.org/10.1152/physiolgenomics.00239.2005.

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Tub is a member of a small gene family, the tubby-like proteins (TULPs), with predominant expression in neurons. Mice carrying a mutation in Tub develop retinal and cochlear degeneration as well as late-onset obesity with insulin resistance. During behavioral and metabolic testing, we found that homozygous C57BL/6J- Tub tub mice have a lower respiratory quotient than C57BL/6J controls before the onset of obesity, indicating that tubby homozygotes fail to activate carbohydrate metabolism and instead rely on fat metabolism for energy needs. In concordance with this, tubby mice show higher excretion of ketone bodies and accumulation of glycogen in the liver. Quantitation of liver mRNA levels shows that, during the transition from light to dark period, tubby mice fail to induce glucose-6-phosphate dehydrogenase ( G6pdh), the rate-limiting enzyme in the pentose phosphate pathway that normally supplies NADPH for de novo fatty acid synthesis and glutathione reduction. Reduced G6PDH protein levels and enzymatic activity in tubby mice lead accordingly to lower levels of NADPH and reduced glutathione (GSH), respectively. mRNA levels for the lipolytic enzymes acetyl-CoA synthetase and carnitine palmitoyltransferase are increased during the dark cycle and decreased during the light period, and several citric acid cycle genes are dysregulated in tubby mice. Examination of hypothalamic gene expression showed high levels of preproorexin mRNA leading to accumulation of orexin peptide in the lateral hypothalamus. We hypothesize that abnormal hypothalamic orexin expression leads to changes in liver carbohydrate metabolism and may contribute to the moderate obesity observed in tubby mice.

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Dziadek, Sebastian, Sandra Jacques et David R Bundle. « A Novel Linker Methodology for the Synthesis of Tailored Conjugate Vaccines Composed of Complex Carbohydrate Antigens and Specific TH‐Cell Peptide Epitopes ». Chemistry - A European Journal 14, n^o 19 (27 juin 2008) : 5908–17. http://dx.doi.org/10.1002/chem.200800065.

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Zeuner, Birgitte, David Teze, Jan Muschiol et Anne S. Meyer. « Synthesis of Human Milk Oligosaccharides : Protein Engineering Strategies for Improved Enzymatic Transglycosylation ». Molecules 24, n^o 11 (28 mai 2019) : 2033. http://dx.doi.org/10.3390/molecules24112033.

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Human milk oligosaccharides (HMOs) signify a unique group of oligosaccharides in breast milk, which is of major importance for infant health and development. The functional benefits of HMOs create an enormous impetus for biosynthetic production of HMOs for use as additives in infant formula and other products. HMO molecules can be synthesized chemically, via fermentation, and by enzymatic synthesis. This treatise discusses these different techniques, with particular focus on harnessing enzymes for controlled enzymatic synthesis of HMO molecules. In order to foster precise and high-yield enzymatic synthesis, several novel protein engineering approaches have been reported, mainly concerning changing glycoside hydrolases to catalyze relevant transglycosylations. The protein engineering strategies for these enzymes range from rationally modifying specific catalytic residues, over targeted subsite −1 mutations, to unique and novel transplantations of designed peptide sequences near the active site, so-called loop engineering. These strategies have proven useful to foster enhanced transglycosylation to promote different types of HMO synthesis reactions. The rationale of subsite −1 modification, acceptor binding site matching, and loop engineering, including changes that may alter the spatial arrangement of water in the enzyme active site region, may prove useful for novel enzyme-catalyzed carbohydrate design in general.

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Raposo, G., H. M. van Santen, R. Leijendekker, H. J. Geuze et H. L. Ploegh. « Misfolded major histocompatibility complex class I molecules accumulate in an expanded ER-Golgi intermediate compartment. » Journal of Cell Biology 131, n^o 6 (15 décembre 1995) : 1403–19. http://dx.doi.org/10.1083/jcb.131.6.1403.

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Misfolded membrane proteins are rapidly degraded, often shortly after their synthesis and insertion in the endoplasmic reticulum (ER), but the exact location and mechanisms of breakdown remain unclear. We have exploited the requirement of MHC class I molecules for peptide to achieve their correct conformation: peptide can be withheld by introducing a null mutation for the MHC-encoded peptide transporter, TAP. By withholding TAP-dependent peptides, the vast majority of newly synthesized class I molecules fails to leave the endoplasmic reticulum and is degraded. We used mice transgenic for HLA-B27 on a TAP1-deficient background to allow visualization by immunoelectron microscopy of misfolded HLA-B27 molecules in thymic epithelial cells. In such HLA transgenic animals, the TAP mutation can be considered a genetic switch that allows control over the extent of folding of the protein of interest, HLA-B27, while the rate of synthesis of the constituent subunits remains unaltered. In TAP1-deficient, HLA-B27 transgenic animals, HLA-B27 molecules fail to assemble correctly, and do not undergo carbohydrate modifications associated with the Golgi apparatus, such as conversion to Endoglycosidase H resistance, and acquisition of sialic acids. We show that such molecules accumulate in an expanded network of tubular and fenestrated membranes. This compartment has its counterpart in normal thymic epithelial cells, and is identified as an ER-Golgi intermediate. We detect the presence of ubiquitin and ubiquitin-conjugating enzymes in association with this compartment, suggesting a nonlysosomal mode of degradation of its contents.

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Funtan, Sebastian, Anne Funtan, Reinhard Paschke et Wolfgang H. Binder. « Biomimetic Elastin-Like Polypeptides as Materials for the Activation of Mechanophoric Catalysts ». Organic Materials 02, n^o 02 (avril 2020) : 116–28. http://dx.doi.org/10.1055/s-0040-1702149.

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Elastin-like polypeptides (ELPs) are well known for their elastic and thermoresponsive behaviors. Their elasticity originates from the formation of a β-spiral which is the consequence of stacking type-II β-turns, formed from individual VPGVG pentapeptide units. Here, the synthesis of ELPs of varying chain lengths [VPGVG, (VPGVG)2, and (VPGVG)4] and their coupling to a mechanoresponsive catalyst are reported. The attached ELP chains can act as “molecular springs,” allowing for an efficient uptake and transmission of an applied force to the mechanophoric bond. This leads to stress-induced activation of the mechanophoric catalyst, in turn transforming mechanical energy into a “click” reaction. Secondary structure analysis via IR and CD spectroscopy revealed that the β–spiral formation of the ELP is not affected by the coupling process and the β–spiral is still intact in the mechanocatalyst after the coupling. Mechanochemical activation of the synthesized catalysts by an external applied force, studied via ultrasonication, showed conversions of the copper(I)-catalyzed alkyne-azide “click” reaction (CuAAC) up to 5.6% with an increasing chain length of the peptide, proving the potential to incorporate this chemistry into biomaterial engineering.

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Marcos, Nuno T., Andrea Cruz, Filipe Silva, Raquel Almeida, Leonor David, Ulla Mandel, Henrik Clausen, Silvia von Mensdorff-Pouilly et Celso A. Reis. « Polypeptide GalNAc-transferases, ST6GalNAc-transferase I, and ST3Gal-transferase I Expression in Gastric Carcinoma Cell Lines ». Journal of Histochemistry & ; Cytochemistry 51, n^o 6 (juin 2003) : 761–71. http://dx.doi.org/10.1177/002215540305100607.

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Mucin O-glycosylation in cancer is characterized by aberrant expression of immature carbohydrate structures leading to exposure of simple mucin-type carbohydrate antigens and peptide epitopes. Glycosyltransferases controlling the initial steps of mucin O-glycosylation are responsible for the altered glycosylation observed in cancer. We studied the expression in gastric cell lines of six UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (GalNAc-T1, T2, T3, T4, T6, T11) that catalyze the initial key step in the regulation of mucin O-glycosylation, the transfer of GalNAc from UDP-GalNAc to serine and threonine residues. We also studied the expression of ST6GalNAc-I, the enzyme responsible for the synthesis of Sialyl-Tn antigen (NeuAcα2,6GalNAc) and the ST3Gal-I, the enzyme responsible for the synthesis of Sialyl-T antigen (NeuAcα2,3Galβ1,3GalNAc). This study was done using specific monoclonal antibodies, enzymatic assays, and RT-PCR. Our results showed that GalNAc-T1, -T2, and -T3 have an ubiquitous expression in all gastric cell lines, whereas GalNAc-T4, -T6, and -T11 show a restricted expression pattern. The immunoreactivity with MAb VU-2-G7 suggests that, apart from GalNAc-T4, another GalNAc transferase is involved in the glycosylation of the Thr in the PDTR region of the MUC1 tandem repeat. The expression of ST3Gal-I correlates with the expression of the Sialyl-T antigen in gastric cell lines and in the control cell lines studied. The expression of ST6GalNAc-I is low in gastric cell lines, in accordance with the low/absent expression of the Sialyl-Tn antigen.

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Yang, Haiyan, Yongkang Duan, Zhiwen Wei, Yaqiong Wu, Chunhong Zhang, Wenlong Wu, Lianfei Lyu et Weilin Li. « Integrated Physiological and Metabolomic Analyses Reveal the Differences in the Fruit Quality of the Blueberry Cultivated in Three Soilless Substrates ». Foods 11, n^o 24 (7 décembre 2022) : 3965. http://dx.doi.org/10.3390/foods11243965.

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With improving living standards, traditional blueberry planting modes cannot meet commercial demands, and blueberry cultivation with soilless substrate has become a popular solution in the blueberry industry. In this study, different soilless substrate treatments were found to markedly influence fruit appearance and intrinsic quality. The fruit in the 50:50 peat/pine bark (v/v) (FPB) treatment group had the maximum single fruit weight, largest vertical diameter, and brightest color, as well as the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) value, solid-acid ratio and anthocyanin content. The fruit in the 50:50 pine bark/rice husk (v/v) (FBR) treatment group had the highest total phenol and flavonoid levels, largest drip loss value, and lowest total pectin content and firmness value. Metabolomic analysis showed that flavonoid, carbohydrate, and carbohydrate conjugate, and amino acid, peptide, and analog levels were significantly different between groups. Fruit in the FPB group had the highest sucrose, D-fructose 1,6-bisphosphate, salidroside, tectorigenin, naringenin chalcone, trifolirhizin, and galangin contents. The increase in the relative expression of phenylalanine (Phe) promoted the synthesis of fruit polyphenols in the FBR group. Our results provide new insights into the effects of different substrates on the quality of blueberries and a reference for the soilless substrate cultivation of blueberries.

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Deneka, I. E., A. V. Rodionov et V. V. Fomin. « Treatment of hypertension in obese patients : focus on telmisartan ». Cardiovascular Therapy and Prevention 17, n^o 6 (20 décembre 2018) : 69–76. http://dx.doi.org/10.15829/1728-8800-2018-6-69-76.

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The article discusses the role of telmisartan in the treatment of arterial hypertension in patients with metabolic syndrome. Telmisartan is second-generation type 1 angiotensin II receptor blocker, which has unique pleiotropic effects due to partial affinity for receptors that activate the proliferation of subtype y peroxisomes (PPARy) located in adipose tissue. The interrelation of metaflamation, a specific chronic inflammatory process with pathogenetic mechanisms of development of cardiovascular diseases, including arterial hypertension, is also described in study. The role of the adiponectin peptide is considered, which synthesis is stimulated by partial PPARy receptor agonists (as mentioned above — telmisartan). It has a positive effect on fat and carbohydrate metabolism, as well as cardioprotective properties. The conclusion contains the results of numerous randomized studies and meta-analyzes confirming the high efficacy of telmisartan in the treatment of arterial hypertension in patients with morbid obesity.

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Bovin, Nicolai V. « Neoglycoconjugates : trade and art ». Biochemical Society Symposia 69 (1 octobre 2002) : 143–60. http://dx.doi.org/10.1042/bss0690143.

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This chapter deals with the tendencies in design of multivalent neoglycoconjugates for glycobiology research and high-throughput profiling technologies, including cellular phenotyping. Soluble polyacrylamide (PAA) conjugates are remarkable owing to a variety of possibilities for synthesis and application. PAA is soluble and stable, and the molecule is flexible, PAA-tethered ligands are capable of adjusting to a receptor during multiple-point interactions and PAA does not bind to the cell surface. Synthesis provides unlimited diversity of the probe types (biotin, fluorescein, allyl, digoxygenin, 3H, radiolabelled I), glyco-particles, glyco-surfaces, multiarrays, immunogens etc. Several examples illustrate the most advanced applications. (i) Dynamic systems: the selectin ligands immobilized on the surface as sugar–PAA conjugates made the study of the kinetics of rolling in the model system possible. Carbohydrate ligands that are covalently attached to the chip as sugar–PAA conjugates are of use with the surface plasmon resonance method. (ii) Pseudoglycoprotein: some questions arise regarding the biologically active glycoproteins, e.g.: is a carbohydrate or peptide fragment responsible for the activity? We have proposed the approach that promotes to answer this and other questions. The pool of oligosaccharides that were spitted off a glycoprotein is attached to PAA resulting in a pseudoglycoprotein. (iii) Virtual (dynamic) glycotope: receptor-ligand recognition, such as that of P-selectin with its receptor P-selectin glycoprotein ligand 1, frequently involves molecular interactions at two distinct sites. Using P-selectin as a model, we developed an approach to discover novel ligands. PAA was synthesized with multiple ligands; a marked synergistic inhibitory effect was observed.

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Hebert, Elvira María, Gianfranco Mamone, Gianluca Picariello, Raúl R. Raya, Graciela Savoy, Pasquale Ferranti et Francesco Addeo. « Characterization of the Pattern of αs1- and β-Casein Breakdown and Release of a Bioactive Peptide by a Cell Envelope Proteinase from Lactobacillus delbrueckii subsp. lactis CRL 581 ». Applied and Environmental Microbiology 74, n^o 12 (18 avril 2008) : 3682–89. http://dx.doi.org/10.1128/aem.00247-08.

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ABSTRACT The cell envelope-associated proteinases (CEPs) of the lactobacilli have key roles in bacterial nutrition and contribute to the development of the organoleptic properties of fermented milk products as well, as they can release bioactive health-beneficial peptides from milk proteins. The influence of the peptide supply, carbohydrate source, and osmolites on the CEP activity of the cheese starter Lactobacillus delbrueckii subsp. lactis CRL 581 was investigated. The CEP activity levels were controlled by the peptide content of the growth medium. The maximum activity was observed in a basal minimal defined medium, whereas in the presence of Casitone, Casamino Acids, or yeast extract, the synthesis of CEP was inhibited 99-, 70-, and 68-fold, respectively. The addition of specific di- or tripeptides containing branched-chain amino acids, such as leucylleucine, prolylleucine, leucylglycylglycine, or leucylproline, to the growth medium negatively affected CEP activity, whereas dipeptides without branched-chain amino acids had no effect on the enzyme's production. The carbon source and osmolites did not affect CEP activity. The CEP of L. delbrueckii subsp. lactis CRL 581 exhibited a mixed-type CEPI/III variant caseinolytic specificity. Mass-spectrometric screening of the main peptide peaks isolated by reverse-phase high-pressure liquid chromatography allowed the identification of 33 and 32 peptides in the αs1- and β-casein hydrolysates, respectively. By characterizing the peptide sequence in these hydrolysates, a pattern of αs1- and β-casein breakdown was defined and is reported herein, this being the first report for a CEP of L. delbrueckii subsp. lactis. In this pattern, a series of potentially bioactive peptides (antihypertensive and phosphopeptides) which are encrypted within the precursor protein could be visualized.

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Molenaar, Tom J. M., Chantal C. M. Appeldoorn, Sonja A. M. de Haas, Ingrid N. Michon, Arnaud Bonnefoy, Marc F. Hoylaerts, Hans Pannekoek, Theo J. C. van Berkel, Johan Kuiper et Erik A. L. Biessen. « Specific inhibition of P-selectin–mediated cell adhesion by phage display–derived peptide antagonists ». Blood 100, n^o 10 (15 novembre 2002) : 3570–77. http://dx.doi.org/10.1182/blood-2002-02-0641.

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P-selectin is a leukocyte adhesion receptor expressed on activated vascular endothelium and platelets that mediates leukocyte rolling and attachment. Because P-selectin is critically involved in inflammation, we used phage display libraries to identify P-selectin–specific peptides that might interfere with its proinflammatory function. Isolated phage contained a highly conserved amino acid motif. Synthetic peptides showed calcium-dependent binding to P-selectin, with high selectivity over E-selectin and L-selectin. The peptides completely antagonized adhesion of monocyte-derived HL60 cells to P-selectin and increased their rolling velocities in flow chamber experiments. Peptide truncation and alanine-scanning studies indicated that an EWVDV (single-letter amino acid codes) consensus motif sufficed for effective inhibition. Intriguingly, the apparent avidity of the peptides was increased 200-fold when presented in a tetrameric form (2 μM versus 10 nM), which is consistent with the proposed divalent interaction of P-selectin glycoprotein ligand 1 (PSGL-1) with P-selectin. As the EWVDV peptides inhibit the binding of an established glycoside ligand for P-selectin (sulfated Lewis A), it is conceivable that EWVDV interacts with or in close proximity to the actual carbohydrate recognition domain of P-selectin, without being a direct structural mimic of sialyl Lewisx. These ligands are among the most potent antagonists of P-selectin yet designed. Their high affinity, selectivity, and accessible synthesis provide a promising entry to the development of new anti-inflammatory therapeutics and might be a powerful tool to provide important information on the binding site of P-selectin.

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Articles de revues sur le sujet « SYNTHESIS, BIOMATERIAL, PEPTIDE, CARBOHYDRATE »

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