Relevant bibliographies by topics / Membrane proteins and peptides

Academic literature on the topic 'Membrane proteins and peptides'

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Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Membrane proteins and peptides"

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Schrul, Bianca, Katja Kapp, Irmgard Sinning, and Bernhard Dobberstein. "Signal peptide peptidase (SPP) assembles with substrates and misfolded membrane proteins into distinct oligomeric complexes." Biochemical Journal 427, no. 3 (April 14, 2010): 523–34. http://dx.doi.org/10.1042/bj20091005.

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SPP (signal peptide peptidase) is an aspartyl intramembrane cleaving protease, which processes a subset of signal peptides, and is linked to the quality control of ER (endoplasmic reticulum) membrane proteins. We analysed SPP interactions with signal peptides and other membrane proteins by co-immunoprecipitation assays. We found that SPP interacts specifically and tightly with a large range of newly synthesized membrane proteins, including signal peptides, preproteins and misfolded membrane proteins, but not with all co-expressed type II membrane proteins. Signal peptides are trapped by the catalytically inactive SPP mutant SPPD/A. Preproteins and misfolded membrane proteins interact with both SPP and the SPPD/A mutant, and are not substrates for SPP-mediated intramembrane proteolysis. Proteins interacting with SPP are found in distinct complexes of different sizes. A signal peptide is mainly trapped in a 200 kDa SPP complex, whereas a preprotein is predominantly found in a 600 kDa SPP complex. A misfolded membrane protein is detected in 200, 400 and 600 kDa SPP complexes. We conclude that SPP not only processes signal peptides, but also collects preproteins and misfolded membrane proteins that are destined for disposal.
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Martin, Isabelle, and Jean-Marie Ruysschaert. "Common Properties of Fusion Peptides from Diverse Systems." Bioscience Reports 20, no. 6 (December 1, 2000): 483–500. http://dx.doi.org/10.1023/a:1010454803579.

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Although membrane fusion occurs ubiquitously and continuously in alleukaroytic cells, little is known about the mechanism that governs lipidbilayer fusion associated with any intracellular fusion reactions. Recentstudies of the fusion of enveloped viruses with host cell membranes havehelped to define the fusion process. The identification and characterizationof key proteins involved in fusion reactions have mainly driven recent advancesin our understanding of membrane fusion. The most important denominator amongthe fusion proteins is the fusion peptide. In this review, work done in thelast few years on the molecular mechanism of viral membrane fusion will behighlighted, focusing in particular on the role of the fusion peptide and themodification of the lipid bilayer structure. Much of what is known regardingthe molecular mechanism of viral membrane fusion has been gained using liposomesas model systems in which the molecular components of the membrane and the environmentare strictly controlled. Many amphilphilic peptides have a high affinity forlipid bilayers, but only a few sequences are able to induce membrane fusion. Thepresence of α-helical structure in at least part of the fusion peptideis strongly correlated with activity whereas, γ-structure tends to beless prevalent, associated with non-native experimental conditions, and morerelated to vesicle aggregation than fusion. The specific angle of insertionof the peptides into the membrane plane is also found to be an importantcharacteristic for the fusion process. A shallow penetration, extending onlyto the central aliphatic core region, is likely responsible for the destabilization ofthe lipids required for coalescence of the apposing membranes and fusion.
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Röckendorf, Niels, Christian Nehls, and Thomas Gutsmann. "Design of Membrane Active Peptides Considering Multi-Objective Optimization for Biomedical Application." Membranes 12, no. 2 (February 2, 2022): 180. http://dx.doi.org/10.3390/membranes12020180.

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A multitude of membrane active peptides exists that divides into subclasses, such as cell penetrating peptides (CPPs) capable to enter eukaryotic cells or antimicrobial peptides (AMPs) able to interact with prokaryotic cell envelops. Peptide membrane interactions arise from unique sequence motifs of the peptides that account for particular physicochemical properties. Membrane active peptides are mainly cationic, often primary or secondary amphipathic, and they interact with membranes depending on the composition of the bilayer lipids. Sequences of these peptides consist of short 5–30 amino acid sections derived from natural proteins or synthetic sources. Membrane active peptides can be designed using computational methods or can be identified in screenings of combinatorial libraries. This review focuses on strategies that were successfully applied to the design and optimization of membrane active peptides with respect to the fact that diverse features of successful peptide candidates are prerequisites for biomedical application. Not only membrane activity but also degradation stability in biological environments, propensity to induce resistances, and advantageous toxicological properties are crucial parameters that have to be considered in attempts to design useful membrane active peptides. Reliable assay systems to access the different biological characteristics of numerous membrane active peptides are essential tools for multi-objective peptide optimization.
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Hamasaki, Naotaka, Hiroyuki Kuma, Kazuhisa Ota, Masao Sakaguchi, and Katsuyoshi Mihara. "A new concept in polytopic membrane proteins following from the study of band 3 protein." Biochemistry and Cell Biology 76, no. 5 (October 1, 1998): 729–33. http://dx.doi.org/10.1139/o98-085.

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In the present communication, we introduce a novel concept in multispanning polytopic membrane proteins revealed by the study of the band 3 protein. The transmembrane domain of such proteins can be divided into three categories, that is, hydrophilic loops connecting transmembrane peptides (category 1), portions embedded by peptide-peptide interactions (category 2), and portions embedded by peptide-lipid interactions (category 3). Category 2 peptides of polytopic membrane proteins were found to stably reside in the lipid bilayer without peptide-lipid interactions that had been thought to be essential for transmembrane segments. Category 3 peptides are equivalent to single-spanning segments of bitopic membrane proteins. Three different experiments, namely proteolytic digestion, chemical modification of the band 3 protein, and cell free transcription and translation, were used to categorize the transmembrane peptides.Key words: band 3 protein, transmembrane (TM) peptide, classification of TM, category 2-TM, polytopic membrane protein.
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Kondrashov, Oleg V., Peter I. Kuzmin, and Sergey A. Akimov. "Hydrophobic Mismatch Controls the Mode of Membrane-Mediated Interactions of Transmembrane Peptides." Membranes 12, no. 1 (January 13, 2022): 89. http://dx.doi.org/10.3390/membranes12010089.

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Various cellular processes require the concerted cooperative action of proteins. The possibility for such synchronization implies the occurrence of specific long-range interactions between the involved protein participants. Bilayer lipid membranes can mediate protein–protein interactions via relatively long-range elastic deformations induced by the incorporated proteins. We considered the interactions between transmembrane peptides mediated by elastic deformations using the framework of the theory of elasticity of lipid membranes. An effective peptide shape was assumed to be cylindrical, hourglass-like, or barrel-like. The interaction potentials were obtained for membranes of different thicknesses and elastic rigidities. Cylindrically shaped peptides manifest almost neutral average interactions—they attract each other at short distances and repel at large ones, independently of membrane thickness or rigidity. The hourglass-like peptides repel each other in thin bilayers and strongly attract each other in thicker bilayers. On the contrary, the barrel-like peptides repel each other in thick bilayers and attract each other in thinner membranes. These results potentially provide possible mechanisms of control for the mode of protein–protein interactions in membrane domains with different bilayer thicknesses.
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Khvotchev, Mikhail, and Mikhail Soloviev. "SNARE Modulators and SNARE Mimetic Peptides." Biomolecules 12, no. 12 (November 29, 2022): 1779. http://dx.doi.org/10.3390/biom12121779.

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The soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) proteins play a central role in most forms of intracellular membrane trafficking, a key process that allows for membrane and biocargo shuffling between multiple compartments within the cell and extracellular environment. The structural organization of SNARE proteins is relatively simple, with several intrinsically disordered and folded elements (e.g., SNARE motif, N-terminal domain, transmembrane region) that interact with other SNAREs, SNARE-regulating proteins and biological membranes. In this review, we discuss recent advances in the development of functional peptides that can modify SNARE-binding interfaces and modulate SNARE function. The ability of the relatively short SNARE motif to assemble spontaneously into stable coiled coil tetrahelical bundles has inspired the development of reduced SNARE-mimetic systems that use peptides for biological membrane fusion and for making large supramolecular protein complexes. We evaluate two such systems, based on peptide-nucleic acids (PNAs) and coiled coil peptides. We also review how the self-assembly of SNARE motifs can be exploited to drive on-demand assembly of complex re-engineered polypeptides.
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Bechinger, B., and S. U. Gorr. "Antimicrobial Peptides: Mechanisms of Action and Resistance." Journal of Dental Research 96, no. 3 (November 25, 2016): 254–60. http://dx.doi.org/10.1177/0022034516679973.

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More than 40 antimicrobial peptides and proteins (AMPs) are expressed in the oral cavity. These AMPs have been organized into 6 functional groups, 1 of which, cationic AMPs, has received extensive attention in recent years for their promise as potential antibiotics. The goal of this review is to describe recent advances in our understanding of the diverse mechanisms of action of cationic AMPs and the bacterial resistance against these peptides. The recently developed peptide GL13K is used as an example to illustrate many of the discussed concepts. Cationic AMPs typically exhibit an amphipathic conformation, which allows increased interaction with negatively charged bacterial membranes. Peptides undergo changes in conformation and aggregation state in the presence of membranes; conversely, lipid conformation and packing can adapt to the presence of peptides. As a consequence, a single peptide can act through several mechanisms depending on the peptide’s structure, the peptide:lipid ratio, and the properties of the lipid membrane. Accumulating evidence shows that in addition to acting at the cell membrane, AMPs may act on the cell wall, inhibit protein folding or enzyme activity, or act intracellularly. Therefore, once a peptide has reached the cell wall, cell membrane, or its internal target, the difference in mechanism of action on gram-negative and gram-positive bacteria may be less pronounced than formerly assumed. While AMPs should not cause widespread resistance due to their preferential attack on the cell membrane, in cases where specific protein targets are involved, the possibility exists for genetic mutations and bacterial resistance. Indeed, the potential clinical use of AMPs has raised the concern that resistance to therapeutic AMPs could be associated with resistance to endogenous host-defense peptides. Current evidence suggests that this is a rare event that can be overcome by subtle structural modifications of an AMP.
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Mirsaliotis, Antonis, Daniel Lamb, and David W. Brighty. "Nonhelical Leash and α-Helical Structures Determine the Potency of a Peptide Antagonist of Human T-Cell Leukemia Virus Entry." Journal of Virology 82, no. 10 (February 27, 2008): 4965–73. http://dx.doi.org/10.1128/jvi.02458-07.

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ABSTRACT Viral fusion proteins mediate the entry of enveloped viral particles into cells by inducing fusion of the viral and target cell membranes. Activated fusion proteins undergo a cascade of conformational transitions and ultimately resolve into a compact trimer of hairpins or six-helix bundle structure, which pulls the interacting membranes together to promote lipid mixing. Significantly, synthetic peptides based on a C-terminal region of the trimer of hairpins are potent inhibitors of membrane fusion and viral entry, and such peptides are typically extensively α-helical. In contrast, an atypical peptide inhibitor of human T-cell leukemia virus (HTLV) includes α-helical and nonhelical leash segments. We demonstrate that both the C helix and C-terminal leash are critical to the inhibitory activities of these peptides. Amino acid side chains in the leash and C helix extend into deep hydrophobic pockets at the membrane-proximal end of the HTLV type 1 (HTLV-1) coiled coil, and these contacts are necessary for potent antagonism of membrane fusion. In addition, a single amino acid substitution within the inhibitory peptide improves peptide interaction with the core coiled coil and yields a peptide with enhanced potency. We suggest that the deep pockets on the coiled coil are ideal targets for small-molecule inhibitors of HTLV-1 entry into cells. Moreover, the extended nature of the HTLV-1-inhibitory peptide suggests that such peptides may be intrinsically amenable to modifications designed to improve inhibitory activity. Finally, we propose that leash-like mimetic peptides may be of value as entry inhibitors for other clinically important viral infections.
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Martoglio, B. "Intramembrane proteolysis and post-targeting functions of signal peptides." Biochemical Society Transactions 31, no. 6 (December 1, 2003): 1243–47. http://dx.doi.org/10.1042/bst0311243.

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Signal sequences are the addresses of proteins destined for secretion. In eukaryotic cells, they mediate targeting to the endoplasmic reticulum membrane and insertion into the translocon. Thereafter, signal sequences are cleaved from the pre-protein and liberated into the endoplasmic reticulum membrane. We have recently reported that some liberated signal peptides are further processed by the intramembrane-cleaving aspartic protease signal peptide peptidase. Cleavage in the membrane-spanning portion of the signal peptide promotes the release of signal peptide fragments from the lipid bilayer. Typical processes that include intramembrane proteolysis is the regulatory or signalling function of cleavage products. Likewise, signal peptide fragments liberated upon intramembrane cleavage may promote such post-targeting functions in the cell.
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Clément, B., B. Segui-Real, P. Savagner, H. K. Kleinman, and Y. Yamada. "Hepatocyte attachment to laminin is mediated through multiple receptors." Journal of Cell Biology 110, no. 1 (January 1, 1990): 185–92. http://dx.doi.org/10.1083/jcb.110.1.185.

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The interaction of hepatocytes with the basement membrane glycoprotein laminin was studied using synthetic peptides derived from laminin sequences. Rat hepatocytes bind to laminin and three different sites within the A and B1 chains of laminin were identified. Active laminin peptides include the PA22-2 peptide (close to the carboxyl end of the long arm in the A chain), the RGD-containing peptide, PA21 (in the short arm of the A chain) and the pentapeptide YIGSR (in the short arm of the B1 chain). PA22-2 was the most potent peptide, whereas the other two peptides had somewhat lower activity. Furthermore, hepatocyte attachment to laminin was inhibited by the three peptides, with PA22-2 being the most active. Various proteins from isolated membranes of cell-surface iodinated hepatocytes bound to a laminin affinity column including three immunologically related binding proteins : Mr = 67,000, 45,000, and 32,000. Several proteins--Mr = 80,000, 55,000, and 38,000-36,000--with a lower affinity for laminin were also identified. Affinity chromatography on peptide columns revealed that the PA22-2 peptide specifically bound the Mr = 80,000, 67,000, 45,000, and 32,000 proteins, the PA21 peptide bound the Mr = 45,000 and 38,000-36,000 proteins and the YIGSR peptide column bound the 38,000-36,000 protein. Antisera to a bacterial fusion protein of the 32-kD laminin-binding protein (LBP-32) reacted strongly with the three laminin-binding proteins, Mr = 67,000, 45,000, and 32,000, showing that they are immunologically related. Immunoperoxidase microscopy studies confirmed that these proteins are present within the plasma membrane of the hepatocyte. The antisera inhibited the adhesion of hepatocytes to hepatocytes to laminin by 30%, supporting the finding that these receptors and others mediate the attachment of hepatocytes to several regions of laminin.
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Dissertations / Theses on the topic "Membrane proteins and peptides"

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Käll, Lukas. "Predicting transmembrane topology and signal peptides with hidden Markov models /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-719-7/.

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Oldham, Alexis Jean. "Modulation of lipid domain formation in mixed model systems by proteins and peptides." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r1/oldhama/alexisoldham.pdf.

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Yin, Daniel. "Biophysical investigations into membrane-active peptides and proteins." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:25401447-e37b-4c07-a22d-29718958ac48.

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The inexorable spread of antibiotic or antimicrobial resistance is a global problem, described by the UK Chief Medical Officer to be "as big a threat as terrorism". Due to uncontrolled, unnecessary overuse of antibiotics in medicine and agriculture, bacterial resistance has evolved to even the antibiotics of last resort. Antimicrobial peptides (AMPs) are a promising class of organic molecule that have been proposed to exert a potent antimicrobial effect, which, directly or indirectly, involve complex interactions with cell membranes. Three broad mechanisms have been proposed for AMPs: carpet, barrel-stave and toroidal pore. However, the molecular basis for the mode of action of AMPs, and the relationship between primary structure and antimicrobial activity, remains poorly understood. In this thesis, interactions of membrane-active peptides and proteins with model lipid membranes are studied, to understand better the peptide-lipid interactions of two de novo AMPs and a functionally related protein puroindoline-b (pinB), which is implicated in antimicrobial plant defence. Quartz crystal microbalance (QCM), solid-state nuclear magnetic resonance (ssNMR), electron paramagnetic resonance (EPR) and neutron reflectivity (NR) are used to achieve this. The two AMPs were designed rationally with their primary structure predicted to display specific peptide-lipid interactions. Tilamin (tilted antimicrobial insert) was designed by modifying amhelin (antimicrobial insert), a pore-forming AMP. The modified peptide was predicted to disrupt model membranes mimicking bacterial membranes via a different mode of action to transmembrane barrel stave pore formation. Chom (chopped cecropin mutant) was designed by shortening the length of a natural AMP, cecropin-B, and was predicted to operate via a carpet mechanism. To model the biophysical properties such as morphology, thickness and charge of native membranes, simplified phospholipid liposomes were used to better understand the membrane-perturbing influence of the AMPs, and whether this was correlated with antimicrobial activity. In the presence of anionic model membranes (mimicking Gram-negative inner membranes and Gram-positive membranes), tilamin and chom adopt amphipathic alpha helix conformations as determined by circular dichroism, while remaining unstructured in solution and in the presence of zwitterionic model membranes mimicking mammalian model membranes. Adoption of a folded conformation appears to be important for the lytic effect of the AMPs. Calcein leakage experiments performed show that the AMPs induce leakage of calcein from the interior of anionic liposomes, consistent with the proposal that membrane permeabilisation is important for antimicrobial activity. The peptide-lipid interactions of the AMPs were then probed using QCM and ssNMR, giving mechanistic evidence that chom operates via the carpet mechanism as predicted. The nature of the mode of action of tilamin remained uncertain. From order parameters of lipids in bilayers, obtained using ssNMR upon interaction with tilamin, a toroidal pore mechanism was proposed, along with a new mode of action that caused monoleaflet poration, though it was not possible to resolve the two mechanism based on data obtained from symmetrical vesicles alone. Adapting a newly established protocol to control the leaflet distribution of lipids in model membranes, an asymmetrically distributed nitroxide probe reveals for the first time leaflet-specific peptide-lipid interactions using cw-EPR. Tilamin shows changes in bilayer lipid order parameters that do not match those seen for either an all-surface or transmembrane control peptide, indicating more complex interactions. Unique QCM data, heterogeneous changes in order parameter profiles observed with acylchain 2H ssNMR, as well as a lack of interaction with the inner leaflets of anionic model membranes seen by cw-EPR taken in combination suggest tilamin operates via a more complicated mechanism. Supported by tilt angles obtained by geometric analysis of labelled alanines (GALA) of deuterium-labelled tilamin and atomic force microscopy (AFM) imaging performed with collaborators, the results are consistent with a new mechanism; monolayer poration. The puroindolines are also studied, due to their potential role as antimicrobial proteins in food safety, and in controlling wheat endosperm texture. The mode of insertion of wild-type puroindoline-B (pinB+) and a single-point mutant (pinBs) into bacterial model bilayers was probed for the first time with ssNMR, EPR and NR. In contrast to previous work on monolayers, pinBs does not cause changes in bilayer lipid order in the gel phase, while pinB+ forms a protein layer on the surface of a membrane. The results suggest that in more native-like model membranes, the tryptophan-rich domain (TRD) of pinBs and pinB+ greatly affects the membrane binding properties, with implications for the role of the proteins in vivo.
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Mitchell, Stephen Anthony. "Membrane translocating peptides for the delivery of proteins." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397763.

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Oglęcka, Kamila. "Biophysical studies of membrane interacting peptides derived from viral and Prion proteins." Doctoral thesis, Stockholm University, Department of Biochemistry and Biophysics, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7109.

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This thesis focuses on peptides derived from the Prion, Doppel and Influenza haemagglutinin proteins in the context of bilayer interactions with model membranes and live cells. The studies involve spectroscopic techniques like fluorescence, fluorescence correlation spectroscopy (FCS), circular and linear dichroism (CD and LD), confocal fluorescence microscopy and NMR.

The peptides derived from the Prion and Doppel proteins combined with their subsequent nuclear localization-like sequences, makes them resemble cell-penetrating peptides (CPPs). mPrPp(1-28), corresponding to the first 28 amino acids of the mouse PrP, was shown to translocate across cell membranes, concomitantly causing cell toxicity. Its bovine counterpart bPrPp(1-30) was demonstrated to enter live cells, with and without cargo, mainly via macropinocytosis. The mPrPp(23-50) peptide sequence overlaps with mPrPp(1-28) sharing the KKRPKP sequence believed to encompass the driving force behind translocation. mPrPp(23-50) was however found unable to cross over cell membranes and had virtually no perturbing effects on membranes.

mDplp(1-30), corresponding of the first 30 N-terminal amino acids of the Doppel protein, was demonstrated to be almost as membrane perturbing as melittin. NMR experiments in bicelles implied a transmembrane configuration of its alpha-helix, which was corroborated by LD in vesicle bilayers. The positioning of the induced alpha-helix in transportan was found to be more parallel to the bilayer surface in the same model system.

Positioning of the native Influenza derived fusion peptide in bilayers showed no pH dependence. The glutamic acid enriched variant however, changed its insertion angle from 70 deg to a magic angle alignment relative the membrane normal upon a pH drop from 7.4 to 5.0. Concomitantly, the alpha-helical content dramatically rose from 18% to 52% in partly anionic membranes, while the native peptide’s helicity increased only from 39% to 44% in the same conditions.

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Polozov, Ivan V. "Interactions of class A and class L amphipathic helical peptides with model membranes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0006/NQ30110.pdf.

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Redeby, Theres. "Improved Techniques for Protein Analysis Focusing on Membrane Proteins and Hydrophobic Peptides." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-617.

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McKinley, Laura Ellen. "Neutron reflectivity studies of bacterial membranes, peptides and proteins." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28874.

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This thesis uses neutron and x-ray reflectivity to measure the interfacial structures of three molecular components associated with bacteria. Firstly, the way in which the membrane targeting sequence of a cell division protein interacts with monolayer models for the inner leaflet of the inner membrane of bacteria was measured at the air-water interface. Secondly, the influence of lipopolysaccharide on a monolayer model for the outer leaflet of the outer membrane of Gram-negative bacteria was measured at the air-water interface, as well as how this lipopolysaccharide interacts with an antimicrobial peptide. Finally, the structure of a layer of protein found at the surface of a Gram-positive biofilm was measured at the air-water interface. Binding of the membrane targeting sequence of the MinD protein (MinD-mts) to the inner leaflet of the cytoplasmic membrane is thought to be key for bacterial cell division. Modelling this membrane as a monolayer at the air-water interface, it was found that the insertion of the MinD-mts increased with decreasing lateral pressure within the monolayer, as well as with increasing unsaturation of the lipid components, and the incorporation of cardiolipin into the monolayer. Lipopolysaccharide (LPS) is the major component of Gram-negative outer membranes, such as Escherichia coli, and can be considered as having three structural components: lipid A, a core oligosaccharide, and a variable polysaccharide chain. By incorporating LPS into a model membrane at the air-water interface, it was found that the polysaccharide chain undergoes conformational changes depending on the area per molecule. The effect of the antimicrobial peptide Pexiganan on the structure of this LPS layer was also determined, and was found to insert into the polysaccharide chain layer, but have no impact on the conformation of the chains. In nature, many bacteria live within a biofilm structure. A critical component of the Gram-positive Bacillus subtilis biofilm is a surface active amphipathic protein called BslA, which gives rise to the formation of the highly hydrophobic surface of the biofilm. The kinetics of this film formation, its thickness, and the lateral packing of the protein at the air-water interface, were measured using both neutron and x-ray reflectivity. It was found that a native BslA protein consistently formed the same structural film, whilst the structure of films formed by mutant proteins depended on the conditions under which the film was formed.
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Whiles-Lillig, Jennifer A. "Bicelles : a new system for studying membrane associated peptides and proteins /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3022189.

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Trifunovski, Alexandra. "On nogo signaling regulation /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-906-8/.

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Books on the topic "Membrane proteins and peptides"

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Miguel A. R. B. Castanho. Membrane-active peptides: Methods and results on structure and function. La Jolla, Calif: International University Line, 2009.

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Membrane-active peptides: Methods and results on structure and function. La Jolla, Calif: International University Line, 2009.

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Proteins: Membrane binding and pore formation. New York: Springer Science+Business Media, 2010.

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Demmers, Jeroen Adrianus Antonius. Interactions of transmembrane peptides and proteins with lipid membranes studied by mass spectrometry. [S.l: s.n.], 2002.

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Bobone, Sara. Peptide and Protein Interaction with Membrane Systems. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06434-5.

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Ghirlanda, Giovanna, and Alessandro Senes, eds. Membrane Proteins. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-583-5.

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Azzi, Angelo, Lanfranco Masotti, and Arnaldo Vecli, eds. Membrane Proteins. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-71543-3.

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Abel, E. W., ed. Peptides and Proteins. Cambridge: Royal Society of Chemistry, 2007. http://dx.doi.org/10.1039/9781847551634.

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Udenigwe, Chibuike C., ed. Food Proteins and Peptides. Cambridge: Royal Society of Chemistry, 2021. http://dx.doi.org/10.1039/9781839163425.

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Kim, Se-Kwon, ed. Marine Proteins and Peptides. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118375082.

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Book chapters on the topic "Membrane proteins and peptides"

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Rath, Arianna, and Charles M. Deber. "Design of Transmembrane Peptides: Coping with Sticky Situations." In Membrane Proteins, 197–210. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-583-5_11.

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Deber, Charles M., Christopher J. Brandl, Raisa B. Deber, Lynn C. Hsu, and Xenia K. Young. "Membrane-adjacent regions of receptor proteins." In Peptides, 330–31. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-010-9595-2_100.

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Porcelli, Fernando, Ayyalusamy Ramamoorthy, George Barany, and Gianluigi Veglia. "On the Role of NMR Spectroscopy for Characterization of Antimicrobial Peptides." In Membrane Proteins, 159–80. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-583-5_9.

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Lomize, Andrei L., and Irina D. Pogozheva. "Solvation Models and Computational Prediction of Orientations of Peptides and Proteins in Membranes." In Membrane Proteins, 125–42. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-583-5_7.

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Lensink, Marc F. "Membrane-Associated Proteins and Peptides." In Methods in Molecular Biology, 161–79. Totowa, NJ: Humana Press, 2008. http://dx.doi.org/10.1007/978-1-59745-177-2_9.

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Lensink, Marc F. "Membrane-Associated Proteins and Peptides." In Methods in Molecular Biology, 109–24. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-1465-4_6.

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Fraser, Paul E., and Charles M. Deber. "Modulation of membrane morphology by basic proteins and polypeptides." In Peptides, 60–61. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-010-9595-2_15.

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Anderson, Graeme J., Dennis Chapman, Parvez I. Haris, Ian Clarke-Lewis, Gabor Toth, Istvan Toth, and William A. Gibbons. "Conformational studies of membrane receptor proteins: The IgE receptor." In Peptides, 231–32. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2264-1_79.

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Nishino, N., H. Mihara, Y. Tanaka, K. Kobata, and T. Fujimoto. "De novo design of artificial membrane proteins on atropisomeric porphyrin." In Peptides, 1063–64. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0683-2_360.

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Sharma, R. P., A. M. Mata, I. Matthews, A. G. Lee, and J. M. East. "Probing intermembranous loops of membrane proteins using antipeptide antibodies." In Peptides 1992, 923–24. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1470-7_423.

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Conference papers on the topic "Membrane proteins and peptides"

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Dayal, V. K., A. Hsieh, O. Velasquez, and Y. S. Arkel. "VONWILLEBRAND FRAGMENTS IN CoMMERCIAL FVIII CONCENTRATES." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644053.

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We have previously reported sane of the biochemical character-istics of varioias aomnercial FVIII concentrates. Two-dimensional gel analysis of these preparations indicated the presence of pep-tides in the 30-50 KDa basic region. We also noted a relative decrease of high molecular weight vonWillebrand factor (vWF) multimers on SDS-agarose gels. However, the proportion of low molecular weight vWF fragments seems to be increased as judged by the following studies. After reduction and electrophoresis in SDS- PAGE gels, the proteins in concentrates were electroblotted on to the nitrocellulose membranes. The vWF fragments were detected using sandwich of rabbit anti-human vWF antibody, followed by goat anti-rabbit antibody-horseradish peroxidase conjugate incubation and color development. These studies indicated the ore- senceof several vWF peptides in the 30-50 KDa region of one of the FVIII concentrates. These fragments were not detectable in normal plasma analyzed under identical conditions. In order to investigate any clinical significance of the 30-50 KDa peotides, the following experiments were carried out. A factor VIII concentrate preparation was subjected to electrophoresis in SDS-PAGE gels. After electrobiotting, the proteins nitrocellulose membrane were blocked and then reacted with hemoohilia a plasma. Subsequent reaction with 125I Protein A and autoradiograohy revealed the presence of a peptide in approximately 35 KDa region. A protein band of similar molecular weight also reacted with anti-vWF antibody in a separate identical run. Although the patient plasma did contain an antibody to a 35 KDa peotide, it is not certain whether this peptide is identical to the 35 KDa vWF fragment. The commercial FVIII concentrates that contain 30-59 KDa peptides also demonstrate a relative decrease in high molecular weight vWF mul timers. The possible role of proteolysis in the generation of vWF fragments is under study. The results reported here provide evidence that some of the conmercial FVIII concentrates contain peptides in 30-50 KDa region which are not detectable in normal plasma. Furthermore, sane of these low molecular weight peptides are attributable to vWF fragments.
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D’Souza, S. E., M. H. Ginaberg, S. Lam, and E. A. Plow. "ACTIVATION DEPENDENT ALTERATIONS IN THE CHEMICAL CROSSLINKING OF ARGINYL-GLYCYL-ASPARTIC ACID (RGD) PEPTIDES WITH PLATELET GLYCOPROTEIN (GP) GPIIb-IIIa." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643699.

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The platelet adhesive proteins, fibrinogen, fibronectin and von WillebrandFactor, contain RGD amino acid sequences; RGD-containing peptides inhibit the binding of these adhesive proteins to platelets; and a membrane receptor for these adhesive proteins binds to Arg-Gly-Asp and contains GPIIb-IIIa. The present study was undertaken to characterize the interaction of RGDpeptides with GPIIb-IIIa using a chemical crosslinking approach. A radioiodinated RGD-containing heptapeptide was bound to washed human platelets under conditions at which ≥ 85% of theinteraction was inhibited by excess nonlabeled peptide. After binding of the peptide to platelets for 45 min at22°, a homobifunctional crosslinking reagent was added, and the platelets were extracted and analyzed on polyacrylamide gels. With resting platelets,autoradiography of the gels revealedthat the peptide crosslinked tobothGPIIb and GPIIIa. This interaction wasinhibited by excess nonlabeled peptide but not by certain conservatively substituted RGD peptides. Stimulation of the platelets caused a dramatic increase in crosslinking of the peptide to only one of the two subunitsof GPIIb-IIIa. The stimulus dependentincrease in the crosslinking reactionwas specific and saturable as it was inhibited by RGD peptides in a dose dependent manner. In addition, peptides corresponding in structure to the carboxy terminus of the γ chain of fibrinogen also produced concentration dependent inhibition of the interaction. The increase in crosslinking induced by platelet stimulation was divalent ion dependent. Similar results werealso obtained with a second, larger RGD-containing peptide and with asecond chemical crosslinking reagent.Theseresults indicate that platelet stimulation in the presence of divalent ions causes a change which permitsmoreefficient crosslinking of RGD-containing peptides to only one of the two subunits of GPIIb-IIIa. The results are also compatible with a proximalrelationship of both subunits tothe RGD binding sites on the plateletmembrane.
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Caffrey, Martin. "Lipid Phase Behavior: Databases, Rational Design and Membrane Protein Crystallization." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-192724.

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The relationship that exists between structure and function is a unifying theme in my varied biomembrane-based research activities. It applies equally well to the lipid as to the protein component of membranes. With a view to exploiting information that has been and that is currently being generated in my laboratory, as well as that which exists in the literature, a number of web-accessible, relational databases have been established over the years. These include databases dealing with lipids, detergents and membrane proteins. Those catering to lipids include i) LIPIDAT, a database of thermodynamic information on lipid phases and phase transitions, ii) LIPIDAG, a database of phase diagrams concerning lipid miscibility, and iii) LMSD, a lipid molecular structures database. CMCD is the detergent-based database. It houses critical micelle concentration information on a wide assortment of surfactants under different conditions. The membrane protein data bank (MPDB) was established to provide convenient access to the 3-D structure and related properties of membrane proteins and peptides. The utility and current status of these assorted databases will be described and recommendations will be made for extending their range and usefulness.
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Creasy, M. Austin, and Donald J. Leo. "Modeling Bilayer Systems as Electrical Networks." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3791.

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Bilayers are synthetically made cell membranes that are used to study cell membrane properties or make functional devices that use the properties of the cell membrane components. Lipids and proteins are two of the main components of a cell membrane. Lipids are amphiphilic molecules that can self assemble into organized structures in the presences of water and this self assembly property can be used to form bilayers. Because of the amphiphilic nature of the lipids, a bilayer is impermeable to ion flow. Proteins are the active structures of a cell membrane that opens pores through the membrane for ions and other molecules to pass. Proteins are made from amino acids and have varying properties that depend on its configuration. Some proteins are activated by reactions (chemical, thermal, etc) or gradients induced across the bilayer. One way of testing bilayers to find bilayer properties is to induce a potential gradient across a membrane that induces ion flow and this flow can be measured as an electrical current. But, these pores may be voltage gated or activated by some other stimuli and therefore cannot be modeled as a linear conductor. Usually the conductance of the protein is a nonlinear function of the input that activates the protein. A small system that consists of a single bilayer and protein with few changing components can be easily modeled, but as systems become larger with multiple bilayers, multiple variables, and multiple proteins, the models will become more complex. This paper looks at how to model a system of multiple bilayers and the peptide alamethicin. An analytical expression for this peptide is used to match experimental data and a short study on the sensitivity of the variables is performed.
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LOFTUS, J. C., E. F. Plow, A. L. Frelinger III, M. A. Smith, S. D’ouza, and M. H. Ginsberg. "LOCALIZATION AND CHEMICAL SYNTHESIS OF A DIVALENT CATION REGULATED EPITOPE IN PLATELET MEMBRANE GPIIb." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643959.

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Platelet membrane glycoprotein (GP)IIb-IIIa is a component of a common adhesive protein receptor for fibrinogen, fibronectin, and von Willebrand factor. A monoclonal antibody, PMI-1, defines a divalent cation dependent regulation of the surface orientation of the heavy chain of GPIIb. Exposure of the PMI-1 epitope inversely correlates with the capacity of platelets to bind fibrinogen and aggregate. We have now localized and chemically synthesized this epitope. A 1.1 Kb cDNA clone which directs the synthesis of a fusion protein which bears the PMI-1 epitope was isolated from a lambda gt 11 expression library constructed from mRNA from the human erythroleukemia (HEL) cell line. The position of the N-terminal sequence of the light chain of GPIIb in the deduced amino acid sequence of the clone defined the orientation of the light and heavy chains of GPIIb. Analysis of the amino acid sequence corresponding to the heavy chain of GPIIb identified a single region with a high likelihood of containing a continuous epitope. A synthetic 17 residue peptide, corresponding to the predicted antigenic site, inhibited the binding of PMI-1 to platelets. Two uM peptide was required to inhibit binding 50% in the presence of 1 uM PMI-1, indicating an approximate dissociation constant of 1.5 uM for the peptide-antibody complex. This figure should be compared to a Kd of 0.95 uM (JCI 78:1103, 1986) for PMI-1 binding to GPIIb. A second peptide, corresponding to the region immediately adjacent to the predicted antigenic site, failed to inhibit PMI-1 binding. Neither peptide inhibited the binding of two other monoclonal anti GPIIb-IIIa’s to platelets. The peptides had similar effects on PMI-1 interaction with purified GPIIb-IIIa in detergent solution. These data localize the PMI-1 epitope to a 17 amino acid region located near the carboxyl terminal of the heavy chain of GPIIb. Thus, they chemically define a region of GPIIb whose surface expression reflects the competence of GPIIb-IIIa as a component of a platelet receptor for adhesive proteins.
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Maftouni, Negin, M. Amininasab, and Farshad Kowsari. "Molecular Dynamics Study of Nanobio Membranes." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13277.

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Molecular models of lipid bilayers have ignored the interface of two monolayers of nanobiomembranes in detail by now, however in this paper a new physical model is proposed based on variation of surface tension in the interface of two monolayers of membrane. Experimental results have shown that some peptides and proteins like antimicrobial peptides and cytotoxins are able to change the shape of — or in some cases to destroy — the bilayer membrane during insertion to external monolayer. All interfaces in nanobiomembrane are liquid-liquid type. In this paper appropriate ensembles to simulate liquid/liquid interfaces are presented with special focus on proper ones for surface tension analysis.
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Yesiltas, Betul, Charlotte Jacobsen, Egon B. Hansen, Michael Overgaard, Paolo Marcatili, Pedro Garcia-Moreno, Rasmus K. Mikkelsen, and Simon Gregersen. "Physical and oxidative stability of emulsions stabilized with fractionated potato protein hydrolysates obtained from starch production byproduct: Use of bioinformatics and proteomics." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/xxty9713.

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With the increasing demand for sustainable and functional proteins from alternative sources, it is necessary to use advanced proteomics and bioinformatics tools for more time and cost-efficient research. The identification and release of abundant proteins/peptides from plant-based sources has been gaining significant attention by the food industry in the last decade. Despite its low protein content (1–2%), the magnitude of proteins obtained from the starch industry (~240,000 tons/year) makes potatoes a highly relevant source as a plant-based protein. Previously, we have identified and validated abundant peptides with good emulsifying and antioxidant properties using bioinformatics and proteomics tools as well as in vitro model systems. Using data-driven targeted hydrolysis, we were able to release validated, functional peptides from the potato protein obtained from potato fruit juice, a protein rich by-product of potato starch production. This work focuses on fractionation of potato protein hydrolysates (PPH) obtained through such targeted hydrolysis using trypsin and subsequent fraction characterization. Unfractionated (PPH1) and membrane-fractionated (PPH2 as >10kDa, PPH3 as 10-5kDa, PPH4 as 5-0.8kDa and PPH5 as < 0.8kDa) PPH was characterized for emulsifying and antioxidant properties/potential. Pendant drop technique and dilatational rheology were applied for determining interfacial tension and viscoelasticity of the PPH fractions at the oil-water interface. PPH2 (>10kDa) showed higher decrease of oil-water interfacial tension. All fractions predominantly provided elastic, weak and easily stretchable interfaces. PPH2 provided more rigid interfacial layer than the other fractions. Radical scavenging and metal chelating activities of PPHs were also tested and the best activities were provided by fractions >5kDa. Furthermore, their ability to form physically and oxidatively stable 5% fish oil-in-water emulsions were investigated during 8-day storage and results generally showed that fractions >5kDa provided the best stability followed by the 5–0.8kDa fraction.
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Fresslnaud, E., J. E. Sadler, J. P. Girma, H. R. Baumgartner, and D. Meyer. "SYNTHETIC RGD-CONTAINING PEPTIDES OF VON WILLEBRAND FACTOR INHIBIT PLATELET ADHESION TO COLLAGEN." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643591.

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The Arg-Gly-Asp (RGD) sequence is common to fibrinogen (Fg), fibronectin (Fn) and von Willebrand Factor (vWF). RGD-containing peptides compete for binding of these adhesive proteins to platelet membrane GPIIb/IIIa and inhibit thrombin-induced platelet aggregation as does an unrelated dodecapeptide from the γ Fg COOH terminus (γFg 400-411). We compared in flowing blood the effect of γ Fg 400-411 and of 3 synthetic peptides derived from the sequence of human vWF upon platelet adhesion to collagen. The 3 vWF peptides (13 or 18 aminoacids) contained an RGD sequence in the NH2 (peptide 03), central (peptide 07) or COOH (peptide 02) portions. Collagen was coated onto plastic coverslips and exposed in a parallel-plate perfusion chamber to reconstituted human blood at a shear rate of 2,600 s™1 for 3 min at 37°C. Perfusates contained physiological concentrations of 51 Cr-platelets and red cells in either citrated autologous plasma or modified Tyrode buffer containing 4% human albumin ; in the latter case, the collagen-coated coverslips were preincubated with normal plasma or purified human vWF prior to perfusion. Platelet-collagen interactions were estimated by radioactivity counting and quantitative morphometry. RGD peptides 02, 03 and 07 inhibited platelet-collagen interactions in a dose-dependent manner. With peptide 07, deposition of 51 Cr-platelets decreased from 283.8 ± 32.5 × 105/cm2 (mean ± SEM, n = 3) with buffer to 169.6 ± 33.0 in the presence of 50 μM peptide (p < 0.05), 133.7 ± 26.4 with 150 uM (p <0.012) and 101.8 ± 27.1 with 300 uM (p <0.005). The inhibitory effect of γ Fg 400-411 upon platelet deposition was less significant than that of the RGD peptides at 50 and 150 uM concentrations (224.4 ± 39.8, N.S. and 139.5 ± 55.3, p < 0.05, respectively). RGD peptide 07 also inhibited in a dose-dependent way both platelet adhesion to collagen and thrombus growth. Similar results were observed with peptides 02 and 03, indicating that the position of the RGD sequence is not critical. No synergetic effect between RGD and γFg 400-411 peptides was observed. These results with vWF peptides confirm that GPIIb/IIIa is involved not only In platelet aggregation (thrombus growth) but also in vWF-mediated platelet adhesion to collagen.
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Zafar, Rasheeda, and Daniel A. Walz. "PURIFICATION AND PROPERTIES OF HUMAN PLATELET MEMBRANE GLYCOPROTEIN V (GP-V)." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643907.

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Platelet membrane glycoproteins function as specific ligand receptors or substrates for selected platelet agonists and antagonists. GP-V is the only such membrane glycoprotein known to be a thrombin substrate. We have purified GP-V to homogeneity in order to better characterize the nature and specificity of this thrombin proteolysis. GP-V was extracted from fresh human platelets and purified through a combination of gel filtration, hydroxylapatite, DEAE and mono S chromatographies. The resulting protein had a molecular mass of 80 kDa by both non-reduced and reduced SDS electrophoresis. AminortemtnaJ analyses of GP-V failerLto yield any detectable residues, suggesting a blocked N-terminus. Incubation of purified GP-V with 1 nM human thrombin for 20 minutes resulted in the generation of a stable (thrombin resistant) fragment of 63 kDa; smaller GP-V peptides have not been identified. The amino-terminus of the 63 kDa GP-V fragment is also blocked, indicating that thrombin proteolysis is occurring at the carboxyl-terminal region of the protein. Purified GP-V is also a substrate for human γ-thrombin, although its rate of proteolysis is much slower than that observed using γ-thrombin; the 㬱- and γ-thrombin generated GP-V fragments are electrophoretically similar. Polyclonal antibodies raised against purified GP-V react equally with the GP-V fragment. Such antibodies have been used in immunoblotting procedures to screen bovine platelets, human endothelial cells and a transformed erythroid cell line known to express other platelet proteins; all these cells failed to give a positive reaction, suggesting the absence of GP-V in these cell membranes or its presence in an amount significantly lower than that observed for human platelets.
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Shameli, Seyed Mostafa, Caglar Elbuken, Carolyn L. Ren, and Janusz Pawliszyn. "Integration of a PDMS/SU-8/Quartz Microfluidic Chip With a Novel Macroporous Poly Dimethylsiloxane (PDMS) Membrane for Isoelectric Focusing of Proteins Using Whole-Channel Imaging Detection." In ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30805.

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Capillary isoelectric focusing (CIEF) is a high-resolution capillary electrophoresis (CE) technique for separating zwitterionic biomolecules, such as proteins and peptides. In this method, by generating a stable pH gradient along the length of the capillary and under the influence of a constant electric field, samples can be separated according to their different isoelectric points (pI). For identifying the focused zones in CIEF, the whole column imaging detection (WCID) is more reliable than any other single point detection methods since it avoids the need of focused peak mobilization, presenting several advantages such as lower detection time, minimized peak dispersion and consequently higher resolution. Capillary-based IEF-WCID has been invented by Convergent Bioscience Inc. (iCE280 analyzer) for separation of proteins and biomarkers [1–2]. In the iCE280 analyzer, hollow fibers are glued to the capillary to separate electrolytes from the samples and a metal slit with a 65 μm opening is glued to the top of the capillary to improve detection sensitivity by blocking stray light. However, this method has several limitations because of the use of capillary such as low throughput, difficulty to be integrated with other separation modes and low detection sensitivity.
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Reports on the topic "Membrane proteins and peptides"

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Wong, Eric A., and Zehava Uni. Nutrition of the Developing Chick Embryo: Nutrient Uptake Systems of the Yolk Sac Membrane and Embryonic Intestine. United States Department of Agriculture, June 2012. http://dx.doi.org/10.32747/2012.7697119.bard.

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We have examined the developmental changes in composition, amount, and uptake of yolk nutrients (fat, protein, water and carbohydrates) and the expression ofnutrient transporters in the yolk sac membrane (YSM) from embryonic day 11 (Ell) to 21 (E21) and small intestine from embryonic day 15 (E15) to E21 in embryos from young (22-25 wk) and old (45-50 wk) Cobb and Leghorn breeder flocks. The developmental expression profiles for the peptide transporter 1 (PepTl), the amino acid transporters, EAAT3, CAT-1 and BOAT, the sodium glucose transporter (SGLTl), the fructose transporter (GLUT5), the digestive enzymes aminopeptidase N (APN) and sucraseisomaltase (SI) were assayed by the absolute quantification real time PCR method in the YSM and embryonic intestine. Different temporal patterns of expression were observed for these genes. The effect of in ovo injection of peptides (the dipeptide Gly-Sar, purified peptides, trypsin hydrolysate) on transporter gene expression has been examined in the embryonic intestine. Injection of a partial protein hydrolysate resulted in an increase in expression of the peptide transporter PepT2. We have initiated a transcriptome analysis of genes expressed in the YSM at different developmental ages to better understand the function of the YSM.
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Christopher, David A., and Avihai Danon. Plant Adaptation to Light Stress: Genetic Regulatory Mechanisms. United States Department of Agriculture, May 2004. http://dx.doi.org/10.32747/2004.7586534.bard.

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Original Objectives: 1. Purify and biochemically characterize RB60 orthologs in higher plant chloroplasts; 2. Clone the gene(s) encoding plant RB60 orthologs and determine their structure and expression; 3. Manipulate the expression of RB60; 4. Assay the effects of altered RB60 expression on thylakoid biogenesis and photosynthetic function in plants exposed to different light conditions. In addition, we also examined the gene structure and expression of RB60 orthologs in the non-vascular plant, Physcomitrella patens and cloned the poly(A)-binding protein orthologue (43 kDa RB47-like protein). This protein is believed to a partner that interacts with RB60 to bind to the psbA5' UTR. Thus, to obtain a comprehensive view of RB60 function requires analysis of its biochemical partners such as RB43. Background & Achievements: High levels of sunlight reduce photosynthesis in plants by damaging the photo system II reaction center (PSII) subunits, such as D1 (encoded by the chloroplast tpsbAgene). When the rate of D1 synthesis is less than the rate of photo damage, photo inhibition occurs and plant growth is decreased. Plants use light-activated translation and enhanced psbAmRNA stability to maintain D1 synthesis and replace the photo damaged 01. Despite the importance to photosynthetic capacity, these mechanisms are poorly understood in plants. One intriguing model derived from the algal chloroplast system, Chlamydomonas, implicates the role of three proteins (RB60, RB47, RB38) that bind to the psbAmRNA 5' untranslated leader (5' UTR) in the light to activate translation or enhance mRNA stability. RB60 is the key enzyme, protein D1sulfide isomerase (Pill), that regulates the psbA-RN :Binding proteins (RB's) by way of light-mediated redox potentials generated by the photosystems. However, proteins with these functions have not been described from higher plants. We provided compelling evidence for the existence of RB60, RB47 and RB38 orthologs in the vascular plant, Arabidopsis. Using gel mobility shift, Rnase protection and UV-crosslinking assays, we have shown that a dithiol redox mechanism which resembles a Pill (RB60) activity regulates the interaction of 43- and 30-kDa proteins with a thermolabile stem-loop in the 5' UTR of the psbAmRNA from Arabidopsis. We discovered, in Arabidopsis, the PD1 gene family consists of II members that differ in polypeptide length from 361 to 566 amino acids, presence of signal peptides, KDEL motifs, and the number and positions of thioredoxin domains. PD1's catalyze the reversible formation an disomerization of disulfide bonds necessary for the proper folding, assembly, activity, and secretion of numerous enzymes and structural proteins. PD1's have also evolved novel cellular redox functions, as single enzymes and as subunits of protein complexes in organelles. We provide evidence that at least one Pill is localized to the chloroplast. We have used PDI-specific polyclonal and monoclonal antisera to characterize the PD1 (55 kDa) in the chloroplast that is unevenly distributed between the stroma and pellet (containing membranes, DNA, polysomes, starch), being three-fold more abundant in the pellet phase. PD1-55 levels increase with light intensity and it assembles into a high molecular weight complex of ~230 kDa as determined on native blue gels. In vitro translation of all 11 different Pill's followed by microsomal membrane processing reactions were used to differentiate among PD1's localized in the endoplasmic reticulum or other organelles. These results will provide.1e insights into redox regulatory mechanisms involved in adaptation of the photosynthetic apparatus to light stress. Elucidating the genetic mechanisms and factors regulating chloroplast photosynthetic genes is important for developing strategies to improve photosynthetic efficiency, crop productivity and adaptation to high light environments.
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Mevarech, Moshe, Jeremy Bruenn, and Yigal Koltin. Virus Encoded Toxin of the Corn Smut Ustilago Maydis - Isolation of Receptors and Mapping Functional Domains. United States Department of Agriculture, September 1995. http://dx.doi.org/10.32747/1995.7613022.bard.

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Ustilago maydis is a fungal pathogen of maize. Some strains of U. maydis encode secreted polypeptide toxins capable of killing other susceptible strains of U. maydis. Resistance to the toxins is conferred by recessive nuclear genes. The toxins are encoded by genomic segments of resident double-strande RNA viruses. The best characterized toxin, KP6, is composed of two polypeptides, a and b, which are not covalently linked. It is encoded by P6M2 dsRNA, which has been cloned, sequenced and expressed in a variety of systems. In this study we have shown that the toxin acts on the membranes of sensitive cells and that both polypeptides are required for toxin activity. The toxin has been shown to function by creating new pores in the cell membrane and disrupting ion fluxes. The experiments performed on artificial phospholipid bilayers indicated that KP6 forms large voltage-independent, cation-selective channels. Experiments leading to the resolution of structure-function relationship of the toxin by in vitro analysis have been initiated. During the course of this research the collaboration also yielded X-ray diffracion data of the crystallized a polypeptide. The effect of the toxin on the pathogen has been shown to be receptor-mediated. A potential receptor protein, identified in membrane fractions of sensitive cells, was subjected to tryptic hydrolysis followed by amino-acid analysis. The peptides obtained were used to isolate a cDNA fragment by reverse PCR, which showed 30% sequence homology to the human HLA protein. Analysis of other toxins secreted by U. maydis, KP1 and KP4, have demonstrated that, unlike KP6, they are composed of a single polypeptide. Finally, KP6 has been expressed in transgenic tobacco plants, indicating that accurate processing by Kex2p-like activity occurs in plants as well. Using tobacco as a model system, we determined that active antifungal toxins can be synthesized and targeted to the outside of transgenic plant cells. If this methodology can be applied to other agronomically crop species, then U. maydis toxins may provide a novel means for biological control of pathogenic fungi.
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Woolf, Thomas B., Paul Stewart Crozier, and Mark Jackson Stevens. Molecular dynamics of membrane proteins. Office of Scientific and Technical Information (OSTI), October 2004. http://dx.doi.org/10.2172/919637.

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Shirley, David Noyes, Thomas W. Hunt, W. Michael Brown, Joseph S. Schoeniger, Alexander Slepoy, Kenneth L. Sale, Malin M. Young, Jean-Loup Michel Faulon, and Genetha Anne Gray. Model-building codes for membrane proteins. Office of Scientific and Technical Information (OSTI), January 2005. http://dx.doi.org/10.2172/920776.

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Garrison, W. M. Reaction mechanisms in the radiolysis of peptides, polypeptides and proteins. Office of Scientific and Technical Information (OSTI), January 1985. http://dx.doi.org/10.2172/5415209.

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Smith, H. G. Surface-Bound Membrane-Mimetic Assemblies: Electrostatic Attributes of Integral Membrane Proteins. Fort Belvoir, VA: Defense Technical Information Center, October 1988. http://dx.doi.org/10.21236/ada204381.

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Smith, H. G. Surface-Bound Membrane-Mimetic Assemblies: Electrostatic Attributes of Integral Membrane Proteins. Fort Belvoir, VA: Defense Technical Information Center, June 1991. http://dx.doi.org/10.21236/ada237229.

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Williams, Timothy J., Ramesh Balakrishnan, Brian K. Radak, James C. Phillips, Wei Jiang, Sunhwan Jo, Laxmikant V. Kale, Klaus Schulten, and Benoit Roux. Free Energy Landscapes of Membrane Transport Proteins. Office of Scientific and Technical Information (OSTI), September 2017. http://dx.doi.org/10.2172/1483996.

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Heller, Jonathan. Solid state nuclear magnetic resonance studies of prion peptides and proteins. Office of Scientific and Technical Information (OSTI), August 1997. http://dx.doi.org/10.2172/6428.

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