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Devaux, Floriane. "Synthesis and AFM-based single-molecule force spectroscopy of helical aromatic oligoamide foldamers". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0346.
Pełny tekst źródłaFoldamers are artificial folded molecular architectures inspired by the structures and functions of natural biopolymers. Folding is the process selected by nature to control the conformation of its molecular machinery to carry out chemical functions and mechanical tasks, such as en-zyme catalysis, duplication in nucleic acids, force generation,... During the last decade of research on foldamers, synthetic oligomers able to adopt well- defined and predictable folded conformations, such as helices, have been proposed. Recent progress has shown that stepwise chemical synthesis and molecular design based on aromatic oligoamide backbones enable to produce large helically folded molecular architectures. The shape and stiffness of the backbone, local conformational preferences, specific interactions between distant monomers in sequences, as well as the action of external parameters such as the solvent or the presence of ions, can be combine to induce folding tendency. A remarkable aspect of these architectures is that they can give rise to folded patterns that have no in natural counterparts biopolymer structures. For instance, helices whose diameter varies along the se-quence, helices possessing a handedness inversion centre, herringbone helices have been reported. While the structures of these helical molecules have been well characterized in the solid state by X-ray crystallography, much less is known about their dynamic behavior in solution. Their mechanochemical properties are unknown. The objective of the project is to synthesize various helical nanorchitectures based on an oli-goamide aromatic backbone and to obtain a detailed picture of their dynamical conformation in solution, as well as, their mechanochemical properties, by AFM-based single molecule force spectroscopy
Kirstein, Johanna, Christophe Jung, Christian Hellriegel i Christoph Bräuchle. "Single molecule spectroscopy". Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196553.
Pełny tekst źródłaMaity, Sourav. "Single Molecule Force Spectroscopy of CNGA1". Doctoral thesis, SISSA, 2014. http://hdl.handle.net/20.500.11767/3873.
Pełny tekst źródłaIordanov, Iordan. "Structure and dynamics of the outer membrane protein A from Klebsiella pneumoniae : a joint NMR–SMFS–proteolysis and MS approach". Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1602/.
Pełny tekst źródłaKpOmpA is a two-domain membrane protein from Klebsiella pneumoniae belonging to the outer membrane protein A (OmpA) family. It is composed of a transmembrane ß-barrel with 8 ß-strands and a C-terminal, soluble periplasmic domain. The transmembrane domain presents a significant homology with E. Coli OmpA whose three dimensional structure has been determined by X-ray crystallography and by NMR. The E. Coli homologue can function as an adhesin and invasin, participate in biofilm formation, act as both an immune target and evasin, and serves as a receptor for several bacteriophages. It is assumed that most of these functions involve the four protein loops that emanate from the protein to the exterior of the cell. The difference between KpOmpA and E. Coli OmpA is mostly concentrated in these extracellular loops which are larger in the case of KpOmpA. KpOmpA was shown to activate macrophages and dendritic cells through the TLR2 dependent pathway, and these larger loops are supposed to play a specific role in the interactions with the immune system. Thus the structure and dynamics of these loops is of prime functional significance. The currently available information in this regard, including the NMR structure determined in the IPBS NMR group in 2009, have been obtained so far with recombinant protein samples purified and refolded in detergent micelles. In the present work we first established a reconstitution protocol that allowed the incorporation of the membrane protein in the more native environment of the lipid bilayer and characterised our samples by electron microscopy. SMFS experiments were used to probe the reconstituted KpOmpA unfolding-refolding pathways, exploring the folding mechanisms for ß-barrel proteins and suggesting a novel role for OmpA in the bacterial membrane (in collaboration with the group of D. Müller, ETH Zürich). The C-terminal periplasmic domain of KpOmpA was expressed and purified as a separate product and the feasibility of its structure elucidation by NMR was demonstrated by obtaining a high quality HSQC spectrum. The dynamic behaviour of the extracellular portion of the KpOmpA membrane domain reconstituted in liposomes has been investigated by solid state MAS NMR relaxation experiments. We confirmed that the previously observed gradient of dynamic along the molecule axis is an intrinsic property of the protein. Limited proteolysis and MALDI-TOF experiments were coupled with the NMR information in order to assess more precisely the different mobility levels in the loops. Evolutional preservation of the different loops regions is related to their observed flexibility, pointing towards immunologically important, variable, dynamic and accessible loops sections
Howard, John Brooks. "Double point contact single molecule absorption spectroscopy". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31648.
Pełny tekst źródłaCommittee Chair: Marchenkov, Alexei; Committee Member: Davidovic, Dragomir; Committee Member: Gole, James; Committee Member: Hunt, William; Committee Member: Reido, Elisa. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Gryte, Kristofer. "Analysis methods for single molecule fluorescence spectroscopy". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:148969c6-78aa-49c2-8f0e-2d5e5018fd98.
Pełny tekst źródłaRadiom, Milad. "Correlation Force Spectroscopy for Single Molecule Measurements". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/49677.
Pełny tekst źródłaPh. D.
Iljina, Marija. "Aggregation of alpha-synuclein using single-molecule spectroscopy". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/263216.
Pełny tekst źródłaCORTI, ROBERTA. "Single molecule force spectroscopy of proteins and DNA". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/273770.
Pełny tekst źródłaIn the last few decades, the constant development of novel single molecule techniques has created the basis for a new paradigm in the field of biophysics. Among all, the nanomanipulation of individual biomolecules revealed new insights into the mechanics of biological molecules, in particular proteins and DNA, improving the understanding of the fundamental relation between structural properties and biological functions. Therefore, several single-molecule nanomanipulation methods have been developed, including Atomic Force Microscopy (AFM), Magnetic Tweezers (MT) and Flow Stretching (F-S) coupled with fluorescence. All these technique were employed in this Thesis for the characterisation of biological macromolecules by single molecule force spectroscopy (SMFS). In this Thesis I focus mainly on several aspects of a few different proteins trying to depict a frame in which the strong link between proteins function and their structure can be clarified. With this aim, I study the conformational states of an intrinsically disordered protein (IDP) involved in Parkinson's Disease, the a-synuclein (AS) and the structural change driving the DNA compaction mediated by structural maintenance protein, the condensin. Finally, I present a structural study of a DNA-analogue by thermal shifting essays and single molecule experiments. I included also a technical implementation of a (F-S) combined with TIRF set up to promote the high-speed exchanging buffer for study protein DNA interactions. In the AS single molecule force spectroscopy (SMFS) study, I afford the problem of AS lacking of well defined structure by stretching and unfolding a single polyprotein containing the human AS by employing a SMFS approach. The analysis of the different unfolding pathways gives information about the structural conformation of the protein before the mechanical denaturation. The AS was found to assume three distinct conformational states ranging from a random coil to a highly structured conformation. Since ligands, such as Epigallocatechin-3-Gallate (EGCG) and Dopamine (DA), are known to affect the fibrillation process of AS, I used this single molecule technique to investigate the effect of EGCG and DA on the conformational ensemble of the WT AS. Moreover, knowing from several studies that the presence of point mutations, linked to familial PD, correlate with the gaining of structure and therefore with AS aggregation, I SMFS studies also on AS with three different single point mutations (A30P, A53T and E83A). A particular emphasis was given to the comparison between SMFS results and native mass spectrometry data for the conformational changes of AS in the presence of both DA and EGCG. In the following part, related to the DAP: diaminopurine-substituted DNA, a systematic comparison between a wild-type DNA and DAP DNA is performed, in terms of thermal stability and nanomechanical properties, measured at low and high forces. At low forces the DNA extension and bending rigidity were investigated, by using both MT and AFM, while at high forces the overstretching transition behaviour was explored. In the section related to condensin mediated DNA collapsing, I present a single-molecule MT study to measure, in real-time, the compaction of individual DNA molecules by the condensin complex in the presence of ATP. Since many compaction traces showed sudden distinct decreases in the DNA end-to-end length, I present and validate two different very conservative user-bias-independent step-finding algorithm to extract the size of these compaction steps. Finally, a DNA flow stretching implementation is presented. Briefly, several flow cells were tested to achieve a fast buffer exchange in both MT and F-S coupled with TIRF, in the frame of visualisation of DNA:proteins interactions. We validated our flow cells in term of boundary exchange and applied force. We also visualized fluorescent DNA molecules stretched in the presence of several flow rates.
Yang, Shilong 1975. "Theoretical study of single-molecule spectroscopy and vibrational spectroscopy in condensed phases". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30237.
Pełny tekst źródłaIncludes bibliographical references (p. 267-279).
In this thesis, theoretical models and computer simulations are employed to study several problems of single-molecule spectroscopy and vibrational spectroscopy in condensed phases. The first part of the thesis concentrates on studying dynamic disorders probed by single molecule fluorescence spectroscopy. Event statistics and correlations of single-molecule fluorescence sequences of modulated reactions are evaluated for multi-channel model, diffusion-controlled reaction model, and stochastic rate model. Several event-related measurements, such as the on-time correlation and the two-event number density, are proposed to map out the memory function, which characterizes the correlation in the conformational fluctuations. A semiflexible Gaussian chain model is used to determine the statistics and correlations of single-molecule fluorescence resonant energy transfer (FRET) experiments on biological polymers. The distribution functions of the fluorescence lifetime and the FRET efficiency provide direct measures of the chain stiffness and their correlation functions probe the intra-chain dynamics at the single-molecule level. The fluorescence lifetime distribution is decomposed into high order memory functions that can be measured in single- molecule experiments. The scaling of the average fluorescence lifetime on the contour length is predicted with the semi-flexible Gaussian chain model and agrees favorably with recent experiments and computer simulations.
(cont.) To interpret the fluorescence measurements of the mechanical properties of double-stranded DNA, a worm-like chain model is used as a first-principle model to study double-stranded DNA under hydrodynamic flows. The second part of the thesis concentrates on nonperturbative vibrational energy relaxation (VER) effects of vibrational line shapes. In general, nonperturbative and non-Markovian VER effects are demonstrated more strongly on nonlinear vibrational line shapes than on linear absorption.
by Shilong Yang.
Ph.D.
Tojira, Opas. "Single-molecule fluorescence spectroscopy : Implementation of alternating-laser excitation". Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531514.
Pełny tekst źródłaShin, Yongdae. "Single molecule fluorescence spectroscopy of ClpXP-mediated substrate degradation". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50562.
Pełny tekst źródłaIncludes bibliographical references (leaves 67-71).
Energy-dependent proteases, such as ClpXP, are responsible for the regulated destruction of proteins in prokaryotes and organelles of eukaryotes. AAA+ ATPases in these proteases recognize protein substrates and power their mechanical denaturation and subsequent translocation into a sequestered degradation chamber where polypeptide cleavage occurs. Here, we present the single molecule fluorescence assay for probing the interaction between the ClpXP enzyme and its substrates. A covalently crosslinked ClpX hexamer maintain functionally stable form at the low concentration of single molecule level. Surface passivation through polyethylene glycol (PEG) remove unwanted nonspecific binding of substrates, providing specific immobilization of ClpXP protease on the glass surface illuminated by total internal reflection fluorescence (TIRF). Cy3-labeled engineered substrates containing nondegradable GFP in the prescence of ATP[gamma]S form stable pre-engaged substrate-ClpXP complexes where the whole substrate degradation pathway, from unfolding to egress of degraded products, can be monitored without competing with dissociation or additional background characteristic of free labeled substrate in solution. We directly observe some terminal processes that are encountered by ClpXP at the end of substrate degradation process. It is also shown that GFP tail domain stably bind to the ClpX in the presence of ATP[gamma]S and even in the absence of ATP hydrolysis. With the developement of single molecule assay for AAA+ protease, we can expand our knowledge on the mechanism of this crucial motor protein family.
by Yongdae Shin.
S.M.
Kastrup, Lars. "Fluorescence depletion by stimulated emission in single-molecule spectroscopy". [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11513777.
Pełny tekst źródłaPONZELLINI, PAOLO. "Plasmonic nanopores for single molecule spectroscopy towards sequencing applications". Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/939990.
Pełny tekst źródłaViader, Godoy Xavier. "Biophysical properties of single-stranded DNA studied with single-molecule force spectroscopy". Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/670920.
Pełny tekst źródłaEn aquesta tesi hem realitzat experiments fent servir pinces òptiques per tal d’extreure informació precisa sobre les propietats termodinàmiques i cinètiques de diferents sistemes moleculars, posant especial èmfasi en les propietats elàstiques de la cadena simple d’ADN (ssDNA, pel seu acrònim en anglès). La tesi es troba dividida en tres parts. A la primera part s’introdueix de forma general el camp de recerca dels experiments de molècula única, així com s’expliquen els conceptes més bàsics que es desenvoluparan en les parts II i III. La configuració experimental emprada al llarg de tota la tesi, les pinces òptiques, s’introdueix al capítol 2. Per a fer-ho, s’expliquen els principis físics de funcionament de les pinces, que es basen en l’atrapament òptic. Breument, la focalització d’un feix de llum d’alta intensitat permet atrapar i exercir forces en micropartícules dielèctriques (pilotes fetes de plàstic de la mida d’un bacteri), que són recobertes químicament de manera que la molècula d’estudi pot estirar-se, de forma individual, repetides vegades. El capítol 3 conté una breu introducció a les biomolècules que apareixen en aquesta tesi, amb una breu explicació de la seva descoberta, així com la seva estructura i funció (íntimament relacionades). Ens centrem en la descripció de la ssDNA que és el principal objecte d’estudi de la tesi. Al capítol 4 s’introdueixen els models de polímers que s’empren habitualment per a descriure l’elasticitat d’àcids nucleics i proteïnes. En concret, es descriuen els models de la Freely-Jointed Chain i la Worm-Like Chain. La Part II tracta de l’elasticitat de la ssDNA, i inclou els capítols 5, 6 i 7. El capítol 5 es basa en la caracterització de l’elasticitat de la cadena ideal de ssDNA, és a dir, aquella que pot ser modelitzada pels polímers ideals introduïts en el capítol 4. S’estudia l’elasticitat de diferents seqüències de ssDNA, introduint un nou mètode experimental, blocking-splint oligo, per tal d’ampliar el rang de forces estudiat habitualment en molècules curtes (d’una longitud de desenes de bases) de ssDNA. L’estudi mostra la necessitat d’emprar models elàstics extensibles per a la correcte caracterització de l’elasticitat de ssDNA, que explica les discrepàncies existents entre els paràmetres elàstics trobats a la literatura. També hipotetitzem que l’extensibilitat del model pot ser explicada gràcies a la transició experimentada a nivell de nucleòtids: el canvi que experimenta la distància interfosfat de l’ADN es veu modificada segons quina sigui la configuració de l’anell de desoxiribosa. Tot i que és un fenomen molt més conegut en la cadena doble d’ADN, l’apilament-desapilament de bases també s’ha observat en certes seqüències de ssDNA (especialment les que són riques en contingut de purines). Al capítol 6 s’estudien quatre molècules amb un grau d’apilament diferent a partir de les seves corbes força-extensió (FECs). Es desenvolupa un model helix-coil (hèlix-cabdell) per tal d’ajustar les FECs, fet que permet d’obtenir, indirectament, les propietats elàstiques de la cadena apilada. També s’estudia la dependència d’aquesta transició variant la concentració de sal dels experiments en més de dos ordres de magnitud. A través d’aquests experiments, trobem una dependència amb la concentració de sal de l’energia lliure de formació de l’apilament de la ssDNA, fet que ens permet explicar, parcialment, la dependència que es troba en la literatura per la hibridació de la cadena doble d’ADN. El capítol 7 tracta de la formació d’estructures no específiques que apareixen a forces baixes i a concentració de sal alta per a molècules de ssDNA de més de ~100bases. Es proposa un model helix-coil amb cooperativitat per tal de caracteritzar propietats de camp mitjà de les estructures estudiades. S’estudien vuit seqüències diferents, entre 120 i ~14000 bases, i es caracteritza el seu desviament respecte de la corba elàstica ideal amb el model. També s’estudia la dependència de l’estructura secundària de la ssDNA en funció de la concentració de la sal. Analitzant experiments variant la concentració de MgCl2 i NaCl, aconseguim reproduir les FECs a partir de fer dependre els paràmetres del model amb la sal. Finalment, el model desenvolupat ens permet predir la formació d’estructura secundària a força zero (fet que no podem detectar directament a partir d’experiments d’espectroscopia de forces). Es comparen les previsions del model amb les trobades per Mfold, trobant una compatibilitat per als resultats per a molècules de de menys de 1000 bases. La darrera part se centra en col·laboracions que he fet durant a tesi i que necessiten una determinació precisa de les propietats elàstiques de la ssDNA. Al capítol 8 s’estudia la interacció entre l’helicasa del bacteri E. coli i l’ADN, que s’encarrega d’obrir la cadena doble d’ADN, alliberant ssDNA. S’extreuen les seves propietats cinètiques, com la velocitat de translocació – obtenim, independentment de la força aplicada, d’uns 50bp/s, d’acord amb la literatura –. També n’estudiem les seves propietats termodinàmiques, a partir del Teorema de Fluctuació. Finalment, al capítol 9 s’estudien els efectes de certs defectes en molècules d’ADN. A partir d’experiments fora de l’equilibri s’extrau la penalització que suposa per a la hibridització d’ADN la presència d’aquestes bases no complementàries (és a dir, que no són enllaços de A-T o G-C).
Dunn, James Albert. "Single Molecule Characterization of Peptide/Hematite Binding". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494014864020062.
Pełny tekst źródłaDuchi, Llumigusin Diego Armando. "Single-molecule studies of transcription initiation". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:fa5d7117-4270-4362-95f4-ce1c870f2921.
Pełny tekst źródłaKurtz, Andrea H. "Probing single-stranded DNA structure and conformational transitions with single-molecule fluorescence spectroscopy /". May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Pełny tekst źródłaDhital, Bharat. "Single-molecule interfacial electron transfer dynamics in solar energy conversion". Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1477997482545831.
Pełny tekst źródłaBippes, Christian Alexander. "Investigation of biological macromolecules using atomic force microscope-based techniques". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-23734.
Pełny tekst źródłaOpfer, Jan. "Single-molecule force spectroscopy studies of integrin-mediated cell signaling". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-148393.
Pełny tekst źródłaNieder, Jana Berit [Verfasser]. "Single-molecule spectroscopy on pigment-protein complexes / Jana Berit Nieder". Berlin : Freie Universität Berlin, 2011. http://d-nb.info/102593881X/34.
Pełny tekst źródłaMarshall, Addison Robert Lee. "Surface enhanced Raman spectroscopy for single molecule detection and biosensing". Thesis, University of Hull, 2017. http://hydra.hull.ac.uk/resources/hull:16553.
Pełny tekst źródłaFisher, Brent R. "Time resolved fluorescence of CdSe nanocrystals using single molecule spectroscopy". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33649.
Pełny tekst źródłaVita.
Includes bibliographical references.
A wide variety of spectroscopic studies of CdSe nanocrystals (NCs) are presented in this thesis, all studying some aspect of the temporal evolution of NC fluorescence tinder different conditions. In particular the methods of single molecule spectroscopy are used in many experiments allowing the behavior of individual NCs to be resolved from the blurring effect of averaging over the ensemble. Studies of the excited state lifetime of band edge fluorescence from single NCs reveal multiexponential relaxation dynamics that stem from fluctuations of non-radiative decay rates for the band edge exciton. Analysis of these fluctuations allows us to extract single exponential dynamics by sampling only "maximum-intensity" photons, and we find that this single exponential decay is remarkably uniform across a wide variety of NC samples and sizes. We also investigate luminescence from multiexciton (e.g. biexciton and triexciton) states of nanocrystals at both the ensemble and single NC level.
(cont.) Energy splittings, size and temperature dependencies, quantum yields and lifetimes of multiexciton states are measured and discussed. We show for the first time direct resolution of biexciton emission from single exciton emission using two different techniques, fluorescence line narrowing and single NC spectroscopy. We also study the non-classical light emission properties of single NCs and show how multiexciton emission leads to radiative quantum cascades of single photons in the emission of a single NC. Time resolved studies of fluorescence from NCs in solution environments conclude the thesis. The relationship between lifetime and quantum yield for non-homogeneous ensembles like NCs is studied in chapter 8. We show that a sub-population of non-luminescent nanocrystals can reduce the quantum yield of an ensemble of NCs even though the measured lifetime stays constant. A study of NCs in solution fluorescence correlation spectroscopy (FCS) is presented last. We find that FCS is a capable tool for distinguishing small differences in hydrodynamic radius of NCs in solution. We also find that blinking of NCs may have a significant impact on these FCS measurements.
(cont.) An appendix to this thesis presents a general summary the lifetime of various samples CdSe and CdTe NCs.
by Brent R. Fisher.
Ph.D.
Khalil, Gamal Ezat Abdel-Razek. "Single-Molecule Spectroscopy of Fluorene and Thiophene-Based Organic Semiconductors". Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521976.
Pełny tekst źródłaLu, Maolin. "Single-Molecule Spectroscopy Studies of the Conformational Dynamics of Enzymes". Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1415118092.
Pełny tekst źródłaAsano, Marie. "Design, synthesis and single molecule force spectroscopy of biosynthetic polypeptides". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0163/document.
Pełny tekst źródłaProteins fold by the initial, preferential folding of secondarystructures 1, 2, however surprisingly little is known about the basic mechanicalproperties of isolated α-helices and β-sheets from an experimental standpoint.Previous investigations into studying the generic unfolding behaviour of α-heliceshave proved inconclusive 3-5, and to our knowledge the study of an isolated,intramolecular β-sheet is unprecedented.Bioinspired PEG114-b-poly(L-glutamic acid)85-(2-pyridyl disulphide),PEG114-b-poly(L-lysine)134-(2-pyridyl disulphide) and PEG114-b-poly(Llysine)134–b-PEG114 were designed, synthesized and utilized as model systems toprobe the mechanical properties of α-helix and β-sheet secondary motifs. Theobtained results were shown to be in good agreement with theoretical resultsobtained by utilizing a AGAGIR-based statistical mechanical model 6. Thedifference in unravelling force comparing the helices of poly(L-Lysine) ≈30 pNand poly(L-glutamic acid) ≈20 pN diblock copolymers was attributed to thediffering hydrophobicity of the side chains. The greater hydrophobicity of thelysine allowed greater interactions between the side chains and sterically hinderedrandom helix-coil fluctuations, which lead to a superior α-helix stability. Whenexperiments were conducted in conditions promoting the solubility of the lysineside chains, the interactions decreased to a force of ≈20 pN, similar to the force ofinteractions observed for the poly(L-glutamic acid). We infer that a minimum of≈20 pN is needed to rupture the hydrogen bonding maintaining the α-helix as thisforce was obtained in conditions where the side chain interactions wereminimized.The presence of constant force plateaus and corresponding inflectionsdemonstrates a length independent unfolding force, which supports a turn-by-turnunfolding mechanism for the α-helix.In addition, the greater hydrophobicity of the side chains was suggestedto not only stabilize the α-helix structure, but also to inhibit the formation of anintermediate metastable β-hairpin-like structure when entropic forces dominate.Preliminary studies were also conducted on the PEG114-b-poly(LLysine)134-(2-pyridyl disulphide) system after a α-β transition had been inducedby heat in basic conditions, where an inflection at a much higher force of ≈ 70 pNwas obtained suggesting the formation of a β-sheet interaction.A bottom-up, investigative strategy has thus been successfully proposeddemonstrating the potential of utilizing such artificial systems to simplify andexemplify real biological systems. The comprehension of these simpler isolatedmodels will no doubt aid the understanding of more complex systems
Schüller, Verena. "DNA origami structures for applications in single molecule spectroscopy and nanomedicine". Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-157179.
Pełny tekst źródłaPsychogyiopoulou, Krystallia. "Synthesis, surface spectroscopy and single molecule conductance measurements of some metalloporphyrins". Thesis, University of Liverpool, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422991.
Pełny tekst źródłaMagness, Alastair. "Diagnosing cancer one cell at a time with single molecule spectroscopy". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/57501.
Pełny tekst źródłaFisher, Aidan Antony Edward. "Colloidal synthesis, structural characterisation and single molecule spectroscopy of semiconducting nanocrystals". Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/73443/.
Pełny tekst źródłaAdhikari, Subhasis, i Frank Cichos. "Probe size dependent rotational dynamics in polymer by single molecule spectroscopy". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185732.
Pełny tekst źródłaAdhikari, Subhasis, i Frank Cichos. "Probe size dependent rotational dynamics in polymer by single molecule spectroscopy". Diffusion fundamentals 16 (2011) 77, S. 1-2, 2011. https://ul.qucosa.de/id/qucosa%3A13821.
Pełny tekst źródłaYang, Darren. "Exploring Biomolecular Interactions Through Single-Molecule Force Spectroscopy and Computational Simulation". Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493410.
Pełny tekst źródłaEngineering and Applied Sciences - Applied Physics
Botha, Joshua Leon. "Using single molecule spectroscopy to study fast photoprotective processes in plants". Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60864.
Pełny tekst źródłaDie fundamentele meganismes wat by fotosintese betrokke is skep 'n ideale geleentheid om beginsels te bestudeer wat oor beide klassieke en kwantumskale strek. 'n Beter verstaan van hierdie meganismes sal die ontwikkeling van alternatiewe energiebronne soos goedkoop biobrandstof en meer effektiewe fotovoltaïese selle bevorder. Hierdie verhandeling beskryf die enkelmolekuulspektroskopie-opstelling wat tydens my MSc-graad opgerig is en die onderliggende teorie wat nodig is om die tegniek te verstaan, word bespreek. Die grootste deel van die ontwikkeling van die opstelling het die ontwikkeling van toepassingsgerigte sagteware behels. Die kode van hierdie sagteware word oorsigtelik bepreek. Vervolgens word die resultate van 'n reeks enkelmolekuulspektroskopie-metings beskryf waartydens nie-fotochemiesedowing (NFD) in die geïsoleerde ligversamelingskompleks II (LHCII) van hoër plante bestudeer is. Die vinnige, omkeerbare, energie-afhanklike komponent (qE) van NFD is geëmuleer deur die pH van die oplossing waarin die komplekse opgelos is, te verlaag. Buiten metings van die fluoressensie-intensiteite is tydsgekorreleerde enkelfotontelling ook toegepas om fluoressensieleeftye te meet, wat as 'n indirekte meting van die mate van NFD dien. Die moontlikheid dat dowing plaasvind voordat die opwekkingsenergie die laagste energietoestand in die kompleks bereik, is ontdek en 'n verwantskap tussen intermediêre fluoressensietoestande en hoëfrekwensieskakeling word gelê.
Dissertation (MSc)--University of Pretoria, 2016.
Physics
MSc
Unrestricted
Ye, Fangmao. "Single molecule studies of meso/macro porous silica materials and gradient films". Diss., Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1699.
Pełny tekst źródłaVogelsang, Jan. "Advancing single-molecule fluorescence spectroscopy and super-resolution microscopy with organic fluorophores". Diss., kostenfrei, 2009. http://edoc.ub.uni-muenchen.de/11480/.
Pełny tekst źródłaVongtragool, Suriyakan. "Frequency-domain magnetic resonance spectroscopy on the Mn12-acetate single-molecule magnet". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972905952.
Pełny tekst źródłaKlamecka, Kamila [Verfasser], i Heinrich [Akademischer Betreuer] Leonhardt. "Single-molecule force spectroscopy of biological complexes / Kamila Klamecka ; Betreuer: Heinrich Leonhardt". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1156851874/34.
Pełny tekst źródłaKorlann, You. "Methodology development and biological applications of single molecule fluorescence spectroscopy and microscopy". Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1694502711&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Pełny tekst źródłaFrano, Kristen A. "Surface-Enhanced Raman and Single-Molecule Spectroscopy Studies of Fugitive Artists' Pigments". W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539791830.
Pełny tekst źródłaKirstein, Johanna, Christophe Jung, Christian Hellriegel i Christoph Bräuchle. "Single molecule spectroscopy: translational and rotational diffusion of single fluorescent dyes in nano-structured porous materials". Diffusion fundamentals 2 (2005) 94, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14431.
Pełny tekst źródłaGiri, Dipak. "Single-molecule spectroscopic studies of thin-film chemical gradients". Diss., Kansas State University, 2016. http://hdl.handle.net/2097/35225.
Pełny tekst źródłaDepartment of Chemistry
Daniel A. Higgins
This dissertation describes the application of single molecule spectroscopy and tracking to investigations of the nanoscale properties of thin-film chemical gradients and the transport dynamics of molecules dispersed within and upon these gradients. Chemical gradients are surface bound materials that incorporate gradually changing chemical and/or physical properties. A continuous and gradual change in the properties of gradients are expected and often required for their intended applications, which range from directed growth of cell colonies to combinatorial materials science. In reality, such conditions are almost never met due to spontaneous demixing and dewetting processes that can lead to properties variations on microscopic length scales. A better understanding on the properties of chemical gradients on microscopic length scales will aid in the production of better engineered materials. Single molecule spectroscopy (SMS) allows for gradient properties to be probed on nanometer-to-micrometer length scales. In this dissertation, quantitative measurements of gradient polarity (i.e., dielectric properties) are made along a sol-gel derived thin film that incorporates a macroscopic polarity gradient. These measurements report on the microscopic heterogeneity of the gradient film, and point to the occurrence of phase separation of the polar and nonpolar components along the gradient. Single molecule tracking (SMT) provides an important means to examine the dynamics of molecular mass transport in thin films and on surfaces. In this dissertation, SMT is employed to study mass transport in thin water films condensed over monolayer wettability gradients under ambient environments. The results show that the rate and the mechanism of molecular transport depend on the surface wettability, and on the ambient relative humidity. Finally, wettability gradients have been broadly used to drive the transport of liquid droplets. In this dissertation, these applications are extended to achieve spontaneous stretching of DNA by the propulsion of liquid droplets along the gradient. Single molecule fluorescence imaging of DNA stretched along these gradients demonstrates that hydrophobic surfaces play an important role in DNA stretching. The study also shows the surface tension force acting at the gradient-droplet contact line (interface) to be responsible for DNA elongation and alignment. Overall, single molecule methods have been shown to be highly useful for better understanding the properties of chemical gradients as described in this dissertation.
Wörmke, Stephan. "Single Molecule Spectroscopy on Native and Reconstituted Peridinin-Chlorophyll-Protein Light-Harvesting Complexes". Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-91182.
Pełny tekst źródłaOtt, Wolfgang Bernhard [Verfasser], i Hermann [Akademischer Betreuer] Gaub. "Single molecule force spectroscopy with biological tools / Wolfgang Bernhard Ott ; Betreuer: Hermann Gaub". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1175878677/34.
Pełny tekst źródłaBrown, Frank Leon Halet 1972. "Interactions of light with matter-- applications to single molecule spectroscopy and quantum control". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47482.
Pełny tekst źródłaWörmke, Stephan. "Single molecule spectroscopy on native and reconstituted Peridinin-Chlorophyll-Protein light-harvesting complexes". kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/9118/.
Pełny tekst źródłaVongtragool, Suriyakan. "Frequency domain magnetic resonance spectroscopy on the Mn 12 -acetate single molecule magnet". [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11513999.
Pełny tekst źródłaKim, So Yeon. "Observing protein dynamics and conformational changes by ensemble and single-molecule fluorescence spectroscopy /". May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Pełny tekst źródłaChong, Michael. "Electrically driven fluorescence of single molecule junctions". Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAE022/document.
Pełny tekst źródłaThis thesis presents a study of the optoelectronic properties of molecular junctions performed by scanning tunneling microscopy (STM). First, the molecular structures are synthesized on a Au(111) surface. Then, by manipulation we lift and suspend a molecule between the tip of the STM and the gold surface, creating a single molecule junction. By applying a voltage bias between the tip and the sample, a current is generated, which leads to the excitation of the molecule. This process is mediated by the localized surface plasmon modes of the tip. Eventually, the molecule de-excites in a radiative way, generating a fluorescence signal. We use this technique to study two different molecular junctions. First, an emitting unit (fused-porphyrin) is suspended in the junction by means of organic linkers (oligothiophene). This type of junction generates a narrow-line emission of light whose color is controlled by selecting the chemical structure of the emitting unit. Moreover, control over the linewidth is obtained by progressively detaching the emitting unit from the surface. Also, we observe red-shifted vibronic features that provide a chemical fingerprint of the emitter, and blue- shifted vibronic features that are a sign of hot-luminescence. For the second type of junctions we use graphene nanoribbons (GNRs) of atomically precise width and edge structure. When lifted in the junction, GNRs with a specific type of termination (C-terminated) exhibit a light emission spectrum with a main peak and two red-shifted vibrational features. The main peak is associated to an intra-ribbon transition between a localized state (Tamm) and a delocalized state