Download or read book Biophysical Interactions of Peptides and Their Analogues with Lipid Membranes written by Anja Stulz and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Many drugs, displaying a wide range of structures and diverse applications, can cross or bind to lipid membranes. Quantitative understanding of membrane interactions is thus important for several therapeutic approaches. First, membrane permeabilization represents the dominating mode of action of antimicrobial peptides (AMPs) and their synthetic mimics (SMAMPs). In terms of clinical applications, selectivity for bacterial over mammalian membranes is as important as good activity. Second, membrane interactions might influence loading, retaining, and releasing drugs from lipid-based drug delivery systems in a time controlled and targeted manner. Understanding the binding behaviour of the peptide drug exenatide to lipid membranes is not only important for characterization of its release from vesicular phospholipid gels, but might also help to understand other complex peptide-lipid interactions. The main aim of this thesis was to derive a mechanistic understanding of interactions of peptides and their analogues with model lipid membranes with a focus on the lipid composition of a membrane. Membrane permeabilization induced by AMPs and SMAMPs was quantified by a lifetime-based leakage assay using calcein-loaded vesicles. Different leakage behaviours were identified by considering active concentrations, strengths of individual leakage events, L1, and cumulative kinetics. Further experiments using isothermal titration calorimetry (ITC), monolayer adsorption measurements, and differential scanning calorimetry (DSC) helped to characterize the initial binding of AMPs and SMAMPs to lipid membranes and their propensity to induce electrostatic lipid clustering. Leakage experiments showed that the leakage behaviour changes with both, the structure of the AMP or SMAMP and the lipid composition of the membrane. The activity seems to increase if a membrane-active agent favours a permeabilization mechanism to which the particular lipid composition is especially susceptible. A closer look at kinetic profiles allowed distinguishing leakage induced by asymmetric stress from leakage events that occur stochastically. Very hydrophobic and unselective compounds seem to act mainly by hydrophobically driven asymmetry stress, especially when acting on zwitterionic phosphatidylcholine (PC) membranes. This mechanism brings about poor selectivity because all lipid membranes (bacterial and mammalian) contain a hydrophobic core. Stochastic leakage events, on the other hand, probably depend more on lipid compositions. Negatively charged lipids like phosphatidylglycerol (PG) or cardiolipin (CL) triggered the initial electrostatic attraction of polycationic AMPs or SMAMPs to bacterial membranes. High amounts of phosphatidylethanolamine (PE) seem to counteract the unselective asymmetry stress mechanism. Finally, especially strong leakage events were induced in vesicles containing CL. In this way, compounds that induce only rare leakage events might still be effective. In the second part of the thesis, an ITC fit model was introduced to study complex peptide-lipid interactions based on primary binding of peptide to the lipid layer and secondary binding to pre-bound peptide. Exenatide served as an exemplary peptide that interacts electrostatically with mixed POPC/POPG liposomes and self-associates at Kd = 46 μM. A global fit of various ITC curves revealed that exenatide binds primarily to a binding site at the outer membrane leaflet composed of 2-3 negatively charged POPG and some POPC molecules. Primary binding showed high affinity with a Kd1 of 0.2-0.6 μM, while secondary binding with a Kd2 of 10-46 μM was weaker. ITC was able to quantify primary and secondary binding separately, based on different binding enthalpies. Unlike ITC, other methods such as tryptophan fluorescence and microscale thermophoresis (MST) probably represent only a summary or average of both effects. Many similar ITC data can be found in literature that possibly involve primary and secondary binding effects. Those data could benefit from a fit model as presented in this thesis

Download or read book Peptide Lipid Interactions written by Sidney A. Simon and published by Academic Press. This book was released on 2002-11-13 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains a comprehensive overview of peptide-lipid interactions by leading researchers. The first part covers theoretical concepts, experimental considerations, and thermodynamics. The second part presents new results obtained through site-directed EPR, electron microscopy, NMR, isothermal calorimetry, and fluorescence quenching. The final part covers problems of biological interest, including signal transduction, membrane transport, fusion, and adhesion. Key Features * world-renowned experts * state-of-the-art experimental methods * monolayers, bilayers, biological membranes * theoretical aspects and computer simulations * rafts * synaptic transmission * membrane fusion * signal transduction

Download or read book Biological Soft Matter written by Corinne Nardin and published by John Wiley & Sons. This book was released on 2021-04-06 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological Soft Matter Explore a comprehensive, one-stop reference on biological soft matter written and edited by leading voices in the field Biological Soft Matter: Fundamentals, Properties and Applications delivers a unique and indispensable compilation of up-to-date knowledge and material on biological soft matter. The book presents a thorough overview about biological soft matter, beginning with different substance classes, including proteins, nucleic acids, lipids, and polysaccharides. It goes on to describe a variety of superstructures and aggregated and how they are formed by self-assembly processes like protein folding or crystallization. The distinguished editors have included materials with a special emphasis on macromolecular assembly, including how it applies to lipid membranes, and proteins fibrillization. Biological Soft Matter is a crucial resource for anyone working in the field, compiling information about all important substance classes and their respective roles in forming superstructures. The book is ideal for beginners and experts alike and makes the perfect guide for chemists, physicists, and life scientists with an interest in the area. Readers will also benefit from the inclusion of: An introduction to DNA nano-engineering and DNA-driven nanoparticle assembly Explorations of polysaccharides and glycoproteins, engineered biopolymers, and engineered hydrogels Discussions of macromolecular assemblies, including liquid membranes and small molecule inhibitors for amyloid aggregation A treatment of inorganic nanomaterials as promoters and inhibitors of amyloid fibril formation An examination of a wide variety of natural and artificial polymers Perfect for materials scientists, biochemists, polymer chemists, and protein chemists, Biological Soft Matter: Fundamentals, Properties and Applications will also earn a place in the libraries of biophysicists and physical chemists seeking a one-stop reference summarizing the rapidly evolving topic of biological soft matter.

Download or read book Fluorescent Analogs of Biomolecular Building Blocks written by Marcus Wilhelmsson and published by John Wiley & Sons. This book was released on 2016-04-04 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluorescent Analogs of Biomolecular Building Blocks focuses on the design of fluorescent probes for the four major families of macromolecular building blocks. Compiling the expertise of multiple authors, this book moves from introductory chapters to an exploration of the design, synthesis, and implementation of new fluorescent analogues of biomolecular building blocks, including examples of small-molecule fluorophores and sensors that are part of biomolecular assemblies.

Download or read book Study of Bacteriorhodopsin in a Controlled Lipid Environment written by Vivien Yeh and published by Springer. This book was released on 2018-10-26 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the study of how the properties of nanodiscs, such as lipid composition and size, influence the function of the embedding integral membrane protein, bacteriorhodopsin. The author performed systematic studies to show that the lipid composition and the charge of the hydrophobic head and the structure of hydrophilic tails affect the photocycle pathway of bacteriorhodopsin, which is closely associated with its proton-pumping activity. Furthermore, the author demonstrated a highly efficient method for extracting membrane proteins directly from the biological membrane, preserving protein conformation, function and essential native lipids. This book demonstrates optimization and sample preparation, and presents practical methods of preparing membrane protein-embedded nanodisc samples for biophysical studies, which benefit structural and functional studies in the field of membrane protein characterization, both.

Download or read book Advances in Planar Lipid Bilayers and Liposomes written by Ales Iglic and published by Academic Press. This book was released on 2012-09-04 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Planar Lipid Bilayers and Liposomes volumes cover a broad range of topics, including main arrangements of the reconstituted system, namely planar lipid bilayers as well as spherical liposomes. The invited authors present the latest results of their own research groups in this exciting multidisciplinary field. Incorporates contributions from newcomers and established and experienced researchers Explores the planar lipid bilayer systems and spherical liposomes from both theoretical and experimental perspectives Serves as an indispensable source of information for new scientists

Download or read book Thermal Biophysics of Membranes written by Thomas Heimburg and published by John Wiley & Sons. This book was released on 2008-02-08 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of recent experimental and theoretical developments in the field of the physics of membranes, including new insights from the past decade. The author uses classical thermal physics and physical chemistry to explain our current understanding of the membrane. He looks at domain and 'raft' formation, and discusses it in the context of thermal fluctuations that express themselves in heat capacity and elastic constants. Further topics are lipid-protein interactions, protein binding, and the effect of sterols and anesthetics. Many seemingly unrelated properties of membranes are shown to be intimately intertwined, leading for instance to a coupling between membrane state, domain formation and vesicular shape. This also applies to non-equilibrium phenomena like the propagation of density pulses during nerve activity. Also included is a discussion of the application of computer simulations on membranes. For both students and researchers of biophysics, biochemistry, physical chemistry, and soft matter physics.

Download or read book Giant Vesicles written by Pier Luigi Luisi and published by John Wiley & Sons. This book was released on 2008-04-30 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perspectives in Supramolecular Chemistry Founded by J.-M. Lehn Perspectives in Supramolecular Chemistry reflects research which develops supramolecular structures with specific new properties, such as recognition, transport and simulation of biosystems or new materials. The series covers all areas from theoretical and modelling aspects through organic and inorganic chemistry and biochemistry to materials, solid-state and polymer sciences reflecting the many and varied applications of supramolecular structures in modern chemistry. Giant Vesicles Edited by Pier Luigi Luisi and Peter Walde Institute für Polymere, ETH-Zürich, Switzerland Giant vesicles or giant liposomes are supramolecular assembles of amphiphiles, surface active substances which normally contain one or two hydrophobic chains and one hydrophilic head. Due to their relatively large size, giant vesicles are easily observed by light microscopy. This volume provides an overview of ideas and results obtained from experimental studies as well as theoretical approaches. A wide variety of aspects ranging from pure mathematics and physical considerations to biochemical and biological applications are covered. Historical and fundamental aspects are discussed as well as a range of experimental approaches including the micromanipulation and micro-puncturing of single giant vesicles. 87 international contributors comment on a wide range of issues contained under the five main part headings: Introduction Preparation Methods Basic Theoretical Aspects Physical Properties Chemical and Biological Aspects. Giant Vesicles has been written for researchers in the fields of chemistry, biochemistry and biophysics, working in supra-molecular chemistry, surfactant science, liposome and pharmaceutical sciences.

Download or read book The Biophysics of Cell Membranes written by Richard M. Epand and published by Springer. This book was released on 2017-09-25 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume focuses on the modulation of biological membranes by specific biophysical properties. The readers are introduced to emerging biophysical approaches that mimick specific states (like membrane lipid asymmetry, membrane curvature, lipid flip-flop, lipid phase separation) that are relevant to the functioning of biological membranes. The first chapter describes innovative methods to mimic the prevailing asymmetry in biological membranes by forming asymmetrical membranes made of monolayers with different compositions. One of the chapters illustrates how physical parameters, like curvature and elasticity, can affect and modulate the interactions between lipids and proteins. This volume also describes the sensitivity of certain ion channels to mechanical forces and it presents an analysis of how cell shape is determined by both the cytoskeleton and the lipid domains in the membrane. The last chapter provides evidence that liposomes can be used as a minimal cellular model to reconstitute processes related to the origin of life. Each topic covered in this volume is presented by leading experts in the field who are able to present clear, authoritative and up-to-date reviews. The novelty of the methods proposed and their potential for a deeper molecular description of membrane functioning are particularly relevant experts in the areas of biochemistry, biophysics and cell biology, while also presenting clear and thorough introductions, making the material suitable for students in these fields as well.

Download or read book The Evolving Threat of Antimicrobial Resistance written by World Health Organization and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antibiotic resistance development is a natural process of adaption leading to a limited lifespan of antibiotics. Unnecessary and inappropriate use of antibiotics favours the emergence and spread of resistant bacteria. A crisis has been building up over decades, so that today common and life-threatening infections are becoming difficult or even impossible to treat. It is time to take much stronger action worldwide to avert an ever increasing health and economic burden. A new WHO publication "The evolving threat of antimicrobial resistance--Options for action" describes examples of policy activities that have addressed AMR in different parts of the world. The aim is to raise awareness and to stimulate further coordinated efforts.

Download or read book Molecular and Cellular Biophysics written by Meyer B. Jackson and published by Cambridge University Press. This book was released on 2006-01-12 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular and Cellular Biophysics provides advanced undergraduate and graduate students with a foundation in the basic concepts of biophysics. Students who have taken physical chemistry and calculus courses will find this book an accessible and valuable aid in learning how these concepts can be used in biological research. The text provides a rigorous treatment of the fundamental theories in biophysics and illustrates their application with examples. Conformational transitions of proteins are studied first using thermodynamics, and subsequently with kinetics. Allosteric theory is developed as the synthesis of conformational transitions and association reactions. Basic ideas of thermodynamics and kinetics are applied to topics such as protein folding, enzyme catalysis and ion channel permeation. These concepts are then used as the building blocks in a treatment of membrane excitability. Through these examples, students will gain an understanding of the general importance and broad applicability of biophysical principles to biological problems.

Download or read book Biophysics of the Cell Surface written by Roland Glaser and published by Springer Science & Business Media. This book was released on 2013-03-07 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is common practice to publish conference papers in books or monograph series. This gives some advantage to those who did not have the opportunity to attend the meetings, but it irritates and disappoints others who may have hoped for a set of closely related reviews. With this book we have tried to find a compromise. It presents a selection from the topics which have been discussed in a series of inter national symposia entitled "Biophysics of Cell Surface", held in 1976, 1978, 1981, 1985 and 1988 in the GDR, and subsequently published in the journal STUDIA BIOPHYSICA (volumes 56, 74, 90, 110, 1271. Nearly all the contributors to this book participated in one or more of the meetings. We hope that our choice of topics selected for this book manages to reflect the variety and interest of the broad range of subjects which fall within the scope of membrane biophysics, without taking on the randomness of a scientific car-boot sale. We would like to express our thanks to all colleagues and organ~ isations who helped to realize the conferences and particularly this book. financial support for the symposia of 1985 and 1988 was provided by the IUPAB. A number of topics, reflected in this book, resulted in internat ional cooperations, supported by various organisations. We are especially grateful for the support of UNESCO research project on biophysicS in this respect. The European Bureau (ROSTE) of UNESCO supported the editorial work of this book.

Download or read book Nucleic Acid Transfection written by Wolfgang Bielke and published by Springer Science & Business Media. This book was released on 2010-10-21 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gene Delivery into Mammalian Cells: An Overview on Existing Approaches Employed In Vitro and In Vivo, by Peter Hahn and Elizabeth Scanlan * Strategies for the Preparation of Synthetic Transfection Vectors, by Asier Unciti-Broceta, Matthew N. Bacon, and Mark Bradley * Cationic Lipids: Molecular Structure/Transfection Activity Relationships and Interactions with Biomembranes, by Rumiana Koynova and Boris Tenchov * Hyperbranched Polyamines for Transfection, by Wiebke Fischer, Marcelo Calderon, and Rainer Haag * Carbohydrate Polymers for Nonviral Nucleic Acid Delivery, by Antons Sizovs, Patrick M. McLendon, Sathya Srinivasachari, and Theresa M. Reineke * Cationic Liposome–Nucleic Acid Complexes for Gene Delivery and Silencing: Pathways and Mechanisms for Plasmid DNA and siRNA, by Kai K. Ewert, Alexandra Zidovska, Ayesha Ahmad, Nathan F. Bouxsein, Heather M. Evans, Christopher S. McAllister, Charles E. Samuel, and Cyrus R. Safinya * Chemically Programmed Polymers for Targeted DNA and siRNA Transfection, by Eveline Edith Salcher and Ernst Wagner * Photochemical Internalization: A New Tool for Gene and Oligonucleotide Delivery, by Kristian Berg, Maria Berstad, Lina Prasmickaite, Anette Weyergang, Pål K. Selbo, Ida Hedfors, and Anders Høgset * Visualizing Uptake and Intracellular Trafficking of Gene Carriers by Single-Particle Tracking, by N. Ruthardt and C. Bräuchle

Download or read book Life As a Matter of Fat written by Ole G. Mouritsen and published by Springer Science & Business Media. This book was released on 2005-10-24 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a multi-disciplinary perspective on the physics of life and the particular role played by lipids and the lipid-bilayer component of cell membranes. Emphasizes the physical properties of lipid membranes seen as soft and molecularly structured interfaces. By combining and synthesizing insights obtained from a variety of recent studies, an attempt is made to clarify what membrane structure is and how it can be quantitatively described. Shows how biological function mediated by membranes is controlled by lipid membrane structure and organization on length scales ranging from the size of the individual molecule, across molecular assemblies of proteins and lipid domains in the range of nanometers, to the size of whole cells. Applications of lipids in nano-technology and biomedicine are also described.

Download or read book Coarse Graining of Condensed Phase and Biomolecular Systems written by Gregory A. Voth and published by CRC Press. This book was released on 2008-09-22 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring recent developments in the field, Coarse-Graining of Condensed Phase and Biomolecular Systems examines systematic ways of constructing coarse-grained representations for complex systems. It explains how this approach can be used in the simulation and modeling of condensed phase and biomolecular systems. Assembling some of the most influential, world-renowned researchers in the field, this book covers the latest developments in the coarse-grained molecular dynamics simulation and modeling of condensed phase and biomolecular systems. Each chapter focuses on specific examples of evolving coarse-graining methodologies and presents results for a variety of complex systems. The contributors discuss the minimalist, inversion, and multiscale approaches to coarse-graining, along with the emerging challenges of coarse-graining. They also connect atomic-level information with new coarse-grained representations of complex systems, such as lipid bilayers, proteins, peptides, and DNA.

Download or read book Peptaibiotics written by Claudio Toniolo and published by John Wiley & Sons. This book was released on 2009-05-26 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: Originally a special issue of Chemistry & Biodiversity, this is an excellent overview of the status of contemporary studies in peptaibiotics, covering aspects ranging from the search for novel bioactive compounds to considerations of their membrane-modifying properties.

Download or read book Lipid Domains written by and published by Academic Press. This book was released on 2015-06-08 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current Topics in Membranes is targeted toward scientists and researchers in biochemistry and molecular and cellular biology, providing the necessary membrane research to assist them in discovering the current state of a particular field and in learning where that field is heading. This volume offers an up to date presentation of current knowledge in the field of Lipid Domains. Written by leading experts Contains original material, both textual and illustrative, that should become a very relevant reference material The material is presented in a very comprehensive manner Both researchers in the field and general readers should find relevant and up-to-date information