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Author : Lucille Smith Wright
Publisher :
ISBN 13 :
Total Pages : 196 pages
Book Rating : 4.:/5 (436 download)
Download or read book Interaction of Antimicrobial Peptides with Model Cell Membranes written by Lucille Smith Wright and published by . This book was released on 2000 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Gagandeep K. Sandhu
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (131 download)
Download or read book Interactions of Antimicrobial Peptides (AMPs) with Model Membranes at Different PH Values written by Gagandeep K. Sandhu and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antimicrobial peptides (AMPs) are important components of the innate immune systems of many different organisms. Their amphipathic and cationic characteristics promote interactions with the cell membrane. Gad peptides are rich in histidine, and thus have the potential to exhibit pH-dependent activity. The major focus of this study was to understand how Gad peptides interact with model lipid membranes and how these interactions depend on the peptides' overall charge and the composition of the model membranes. 2H NMR spectroscopy was used to study the effect of Gad peptides on lipid acyl chain order of model lipid bilayers at different pH values. 2H NMR results revealed that membrane disruption by Gad peptides was not pH-dependent. Zeta potential measurements were used to study the binding of Gad peptides to model lipid membranes. The binding studies showed that for both Gad-1 and Gad-2 at low pH, less peptide binds to the membrane and the peptide interacts with a larger number of lipid molecules. Experiments performed with model membranes containing cardiolipin (CL) in the presence of Gad-1 showed that the presence of CL allows the membrane to accommodate more Gad-1. In the presence of CL the peptide binds more strongly with the membrane and interacts with a larger number of lipids. Taken together, these results suggest that Gad peptides might disrupt membrane integrity by clustering anionic lipids. Clustering of anionic lipids away from zwitterionic lipids by cationic AMPs might be a contributing mechanism, which does not exclude other mechanisms, including the carpet mechanism and pore formation. The chemical shift values of 15N NMR spectroscopy can give an insight about the positioning of peptides in lipid bilayer surfaces. 15N NMR observations showed that Gad-1 aligned parallel to the membrane surface. The study of AMP-membrane interactions will help to identify criteria to recognize the important features of natural AMP sequences involved in the antimicrobial action and thus assist in the design of AMP-based antibiotics to help overcome the problem of antimicrobial resistance.
Author : Sidney A. Simon
Publisher : Academic Press
ISBN 13 : 0080925855
Total Pages : 606 pages
Book Rating : 4.0/5 (89 download)
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
Author : Sara Bobone
Publisher : Springer
ISBN 13 : 3319064347
Total Pages : 147 pages
Book Rating : 4.3/5 (19 download)
Download or read book Peptide and Protein Interaction with Membrane Systems written by Sara Bobone and published by Springer. This book was released on 2014-05-31 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: In her thesis, Sara Bobone outlines spectroscopic studies of antimicrobial peptides (AMPs) which are promising lead compounds for drugs used to fight multidrug resistant bacteria. Bobone shows that AMPs interact with liposomes and she clarifies the structure of pores formed by one of these molecules. These results help us to understand how AMPs are selective for bacterial membranes and how their activity can be finely tuned by modifying their sequence. Findings which solve several conundrums debated in the literature for years. In addition, Bobone uses liposomes as nanotemplates for the photopolymerization of hydrogels - exploiting the self- assembly properties of phospholipids. Bobone was able to trap an enzyme using nanometeric particles, while still allowing its activity by the diffusion of substrates and products through the network of the polymer. The innovative nano devices described in this thesis could solve many of the hurdles still hampering the therapeutic application of protein-based drugs.
Author : Robert B. Gennis
Publisher : Springer Science & Business Media
ISBN 13 : 1475720653
Total Pages : 549 pages
Book Rating : 4.4/5 (757 download)
Download or read book Biomembranes written by Robert B. Gennis and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 549 pages. Available in PDF, EPUB and Kindle. Book excerpt: New textbooks at all levels of chemistry appear with great regularity. Some fields like basic biochemistry, organic reaction mechanisms, and chemical thermody namics are well represented by many excellent texts, and new or revised editions are published sufficiently often to keep up with progress in research. However, some areas of chemistry, especially many of those taught at the graduate level, suffer from a real lack of up-to-date textbooks. The most serious needs occur in fields that are rapidly changing. Textbooks in these subjects usually have to be written by scientists actually involved in the research which is advancing the field. It is not often easy to persuade such individuals to set time aside to help spread the knowledge they have accumulated. Our goal, in this series, is to pinpoint areas of chemistry where recent progress has outpaced what is covered in any available textbooks, and then seek out and persuade experts in these fields to produce relatively concise but instructive introductions to their fields. These should serve the needs of one semester or one quarter graduate courses in chemistry and biochemistry. In some cases, the availability of texts in active research areas should help stimulate the creation of new courses.
Author : Katsumi Matsuzaki
Publisher : Springer
ISBN 13 : 9811335885
Total Pages : 304 pages
Book Rating : 4.8/5 (113 download)
Download or read book Antimicrobial Peptides written by Katsumi Matsuzaki and published by Springer. This book was released on 2019-04-12 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an overview of antimicrobial peptides (AMPs), their mechanisms of antimicrobial action, other activities, and various problems that must still be overcome regarding their clinical application. Divided into four major parts, the book begins with a general overview of AMPs (Part I), and subsequently discusses the various mechanisms of antimicrobial action and methods for researching them (Part 2). It then addresses a range of activities other than antimicrobial action, such as cell penetration, antisepsis, anticancer, and immunomodulatory activities (Part 3), and explores the prospects of clinical application from various standpoints such as the selective toxicity, design, and discovery of AMPs (Part 4). A huge number of AMPs have been discovered in plants, insects, and vertebrates including humans, and constitute host defense systems against invading pathogenic microorganisms. Consequently, many attempts have been made to utilize AMPs as antibiotics. AMPs could help to solve the urgent problem of drug-resistant bacteria, and are also promising with regard to sepsis and cancer therapy. Gathering a wealth of information, this book will be a bible for all those seeking to develop antibiotics, anti-sepsis, or anticancer agents based on AMPs.
Author : Nury Paula Santisteban Vela
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (131 download)
Download or read book Interaction of Antimicrobial Peptides with Bacterial Cell Envelopes written by Nury Paula Santisteban Vela and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Antimicrobial peptides (AMPs) are small chains of amino acids with the ability to cause bacterial death. AMPs are usually amphiphilic but diverse in charge and structure. The mechanism or mechanisms that AMPs implement to kill bacteria are still under discussion. Studies in model membranes have widely demonstrated the capacity of AMPs to interact with and disrupt the bacterial cell membrane. There are however, good reasons to suspect that AMP interactions with nonmembrane components of bacteria are important. For instance, there is an enormous discrepancy between the peptide to lipid molar ratio (P:L) necessary to generate membrane disruption in model systems (~ 1:100), and the P:L necessary to stop bacterial growth, i.e. the minimal inhibitory concentration (MIC) (~ 10- 100:1). One potential explanation for this discrepancy is that AMPs may interact with non-membrane components of the bacterial cell envelope. The peptidoglycan (PGN) layer is one of the primary non-membrane components of Gram-positive bacterial cell envelopes and is responsible for cell shape and stability. Currently, there is an open discussion about whether PGN can entrap AMPs and prevent them from reaching the cell membrane or, instead promote the accumulation of AMPs on the cell membrane. The primary experimental approach employed in this thesis was 2H NMR spectroscopy of intact bacteria with 2H-labeled membranes. Specifically, since the quadrupolar splittings obtained from the spectra are proportional to the order parameter of the lipid acyl chains, the spectra reflect the structure and dynamics of the membrane. In particular, 2H NMR spectroscopy allows us to characterize the disruption of lipid bilayers caused by AMPs. In this study, different methods to grow 2H-membrane-enriched bacteria were optimized to obtain 2H NMR spectra of E. coli LA8, E. coli JM109 and B. subtilis. Additionally, 2H NMR was used to observe the level of disruption of the cell membrane of B. subtilis caused by the presence of different AMPs, MSI-78 and BP100. Both MSI-78 and BP100 caused the same level of membrane disruption at similar concentrations. Separately, comparison of the 2H NMR spectra of B. subtilis with intact and compromised PGN layers showed no differences. The lack of change in the spectra of PGN-compromised and PGN intact bacteria indicates that there is no change in the dynamics or structure of the lipid bilayer even with a weakened PGN layer. Finally, the disruption caused by MSI-78 and BP100 was measured in B. subtilis with a compromised PGN layer. The results indicate that there is no change in the level of membrane disruption caused by MSI-78 and BP100 when the PGN layer is partially removed.
Author : Claudia Dannehl
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (935 download)
Download or read book Fragments of the Human Antimicrobial LL-37 and Their Interaction with Model Membranes written by Claudia Dannehl and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed description of the characteristics of antimicrobial peptides (AMPs) is highly demanded, since the resistance against traditional antibiotics is an emerging problem in medicine. They are part of the innate immune system in every organism, and they are very efficient in the protection against bacteria, viruses, fungi and even cancer cells. Their advantage is that their target is the cell membrane, in contrast to antibiotics which disturb the metabolism of the respective cell type. This allows AMPs to be more active and faster. The lack of an efficient therapy for some cancer types and the evolvement of resistance against existing antitumor agents make AMPs promising in cancer therapy besides being an alternative to traditional antibiotics. The aim of this work was the physical-chemical characterization of two fragments of LL-37, a human antimicrobial peptide from the cathelicidin family. The fragments LL-32 and LL-20 exhibited contrary behavior in biological experiments concerning their activity against bacterial cells, human cells and human cancer cells. LL-32 had even a higher activity than LL-37, while LL-20 had almost no effect. The interaction of the two fragments with model membranes was systematically studied in this work to understand their mode of action. Planar lipid films were mainly applied as model systems in combination with IR-spectroscopy and X-ray scattering methods. Circular Dichroism spectroscopy in bulk systems completed the results. In the first approach, the structure of the peptides was determined in aqueous solution and compared to the structure of the peptides at the air/water interface. In bulk, both peptides are in an unstructured conformation. Adsorbed and confined to at the air-water interface, the peptides differ drastically in their surface activity as well as in the secondary structure. While LL-32 transforms into an [alpha]-helix lying flat at the water surface, LL-20 stays partly unstructured. This is in good agreement with the high antimicrobial activity of LL-32. In the second approach, experiments with lipid monolayers as biomimetic models for the cell membrane were performed. It could be shown that the peptides fluidize condensed monolayers of negatively charged DPPG which can be related to the thinning of a bacterial cell membrane. An interaction of the peptides with zwitterionic PCs, as models for mammalian cells, was not clearly observed, even though LL-32 is haemolytic. In the third approach, the lipid monolayers were more adapted to the composition of human erythrocyte membranes by incorporating sphingomyelin (SM) into the PC monolayers. Physical-chemical properties of the lipid films were determined and the influence of the peptides on them was studied. It could be shown that the interaction of the more active LL-32 is strongly increased for heterogeneous lipid films containing both gel and fluid phases, while the interaction of LL-20 with the monolayers was unaffected. The results indicate an interaction of LL-32 with the membrane in a detergent-like way. Additionally, the modelling of the peptide interaction with cancer cells was performed by incorporating some negatively charged lipids into the PC/SM monolayers, but the increased charge had no effect on the interaction of LL-32. It was concluded, that the high anti-cancer activity of the peptide originates from the changed fluidity of cell membrane rather than from the increased surface charge. Furthermore, similarities to the physical-chemical properties of melittin, an AMP from the bee venom, were demonstrated.
Author : T. Musumeci
Publisher : Elsevier Inc. Chapters
ISBN 13 : 0128091851
Total Pages : 24 pages
Book Rating : 4.1/5 (28 download)
Download or read book Drug–biomembrane interaction studies written by T. Musumeci and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antimicrobial agents are from different classes of molecules that suppress multiplication and growth of or kill microorganisms such as bacteria, fungi, or viruses. The precise mechanism of action of some antimicrobial agents is unknown but they must interact with or cross the cell membrane to have an effect. Identification of the damage induced by these compounds is difficult due to the complexity of cell membranes. Studying interactions using membrane models is a first step in obtaining elementary information about the effects of such drugs. We discuss interaction studies in the recent literature that use calorimetric techniques, regarding the mechanism of action or side effects of antimicrobial agents. For interaction studies with mimetic membrane models using DSC analysis, we will try to answer some key questions: (a) Does lipid composition affect the interaction? (b) Does the composition of bilayers influence the secondary structure of a peptide antimicrobial? (c) Does lipid polymorphism influence the activity and toxicity of the molecules? We underline the importance of phospholipids (neutral or anionic) chosen to produce biomembrane vesicles as models for the different studies.
Author : Matthrew Grant Burton
Publisher :
ISBN 13 :
Total Pages : 252 pages
Book Rating : 4.:/5 (113 download)
Download or read book Imaging the Interactions of Antimicrobial Peptides with Model and Living Cellular Membrane Systems written by Matthrew Grant Burton and published by . This book was released on 2016 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Richard M. Epand
Publisher : CRC Press
ISBN 13 : 9780849349263
Total Pages : 422 pages
Book Rating : 4.3/5 (492 download)
Download or read book The Amphipathic Helix written by Richard M. Epand and published by CRC Press. This book was released on 1993-07-09 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Amphipathic Helix is a comprehensive volume discussing amphipathic helices in systems as diverse as serum lipoproteins, lung surfactant, cytotoxic peptides, ion channels, mitochondrial targeting, peptide hormones, G proteins, T-cell recognition, DNA binding proteins, and antifreeze proteins. The book also includes general introductory material that defines amphipathic helices, discusses methods to identify amphipathic helical segments from the amino acid sequence of a protein, illustrates how amphipathic helices can be used in the de novo design of peptide and protein structures, and describes how these helices stabilize protein structures. There is also a section on techniques to determine helix orientation in a membrane environment using polarized attenuated total reflection infrared spectroscopy or solid state NMR spectroscopy. Recent developments on all these topics have been discussed by leading experts in this reference for researchers and students in biochemistry, biophysics, and pharmacology.
Author : Ahmad Arouri
Publisher :
ISBN 13 :
Total Pages : 178 pages
Book Rating : 4.:/5 (455 download)
Download or read book Interaction of Antimicrobial Peptides with Model Lipid Membranes written by Ahmad Arouri and published by . This book was released on 2009 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Shokoofeh Nourbakhsh
Publisher :
ISBN 13 :
Total Pages : 163 pages
Book Rating : 4.:/5 (112 download)
Download or read book Biophysical Modelling of Antimicrobial Peptide's Interactions with Phospholipid and Lipopolysaccharide Membranes written by Shokoofeh Nourbakhsh and published by . This book was released on 2019 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Antimicrobial peptides (AMPs) are naturally-occurring peptide antibiotics. The way they work has inspired a vigorous search for optimized peptide antibiotics for fighting resistant bacteria. Cationic AMPs cleverly utilize their electrostatic interactions with the bacterial membrane to selectively attack bacteria. Here, we first present a physical model of membrane selectivity of these peptides. For this, we use model membranes: phospholipid bilayers, possibly carrying a certain fraction of anionic lipids. The simultaneous presence of several competing effects (e.g., lipid demixing and peptide-peptide interactions), however, poses a serious challenge to theoretical analysis. We first examine critically various models of peptide-membrane interactions and map out one, which incorporates adequately these competing effects as well as the geometry of various regions in membranes, occupied by bound peptides, anionic lipids within the interaction range of each peptide, and those outside this range. This leads to a systematically-improved model for peptide selectivity. Using the model, we relate the peptide's intrinsic (cell-independent) selectivity to an apparent, cell-dependent one, and clarify the relative roles of peptide parameters and cell densities in determining their selectivity. A natural consequence of this relationship is that the selectivity is more sensitive to peptide parameters at low cell densities; as a result, the optimal peptide charge, at which the selectivity is maximized, increases with the cell density such that this notion becomes less meaningful at high cell densities. It also enables us to map out intrinsic selectivity from apparent (cell-dependent) one or biologically-relevant one from "conveniently-measured" selectivity. This effort will benefit our endeavour in optimizing the peptide parameters for their enhanced selectivity in a physiological environment. We extend our effort to examine peptide adsorption on the outer membrane (OM) of Gram-negative bacteria (e.g., Escherichia coli). In particular, we focus our effort on developing a model for the interaction between AMPs and the wild-type lipopolysaccharide (LPS) layer in a biologically relevant medium, containing monovalent and divalent salt ions like Mg2+. This requires a non-trivial generalization of an earlier coarse-grained model, in which the effects of oligosaccharide and O-antigen chains are ignored. In our model, these effects are captured by modelling the LPS layer as forming a polymer brush on top of its anionic phosphate groups. Using this model, we examine how the presence of oligosaccharide and O-antigen chains modifies the binding of antimicrobials to the LPS layer. Our results demonstrate that the presence of the saccharide brush reduces the number of hydrophobically- bound peptides to the polymer-grafted interface of LPS, compared to the deep-rough LPS layer that lacks the polymer brush. Our LPS brush model predicts [sim] 30% reduction of peptide adsorption, which is consistent with recent experimental measurements. This can be attributed to the steric hindrance of the brush or the excluded-volume interaction of the saccharide chains with peptides. At a low cell density limit, we also note that the total number of peptides trapped within the brush is very small, compared to the number of bound peptides on the LPS interface. This implies that the hydrophobic binding of peptides is insensitive to brush lengths. This, however, does not exclude the possibility of kinetic slowing-down of the binding.
Author : Ronald N. MacElhaney
Publisher :
ISBN 13 :
Total Pages : 244 pages
Book Rating : 4.:/5 (247 download)
Download or read book The Interactions of Antimicrobial Peptides with Model Lipid Bilayer and Biological Membranes written by Ronald N. MacElhaney and published by . This book was released on 1999 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Karl Lohner
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (969 download)
Download or read book Antimicrobial Peptides, Cell Membrane and Microbial Surface Interaction written by Karl Lohner and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Luis F. Castillo
Publisher : Springer Science & Business Media
ISBN 13 : 3319015680
Total Pages : 393 pages
Book Rating : 4.3/5 (19 download)
Download or read book Advances in Computational Biology written by Luis F. Castillo and published by Springer Science & Business Media. This book was released on 2013-08-04 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume compiles accepted contributions for the 2nd Edition of the Colombian Computational Biology and Bioinformatics Congress CCBCOL, after a rigorous review process in which 54 papers were accepted for publication from 119 submitted contributions. Bioinformatics and Computational Biology are areas of knowledge that have emerged due to advances that have taken place in the Biological Sciences and its integration with Information Sciences. The expansion of projects involving the study of genomes has led the way in the production of vast amounts of sequence data which needs to be organized, analyzed and stored to understand phenomena associated with living organisms related to their evolution, behavior in different ecosystems, and the development of applications that can be derived from this analysis.
Author : Alan L. Harvey
Publisher : CRC Press
ISBN 13 : 9780471975090
Total Pages : 232 pages
Book Rating : 4.9/5 (75 download)
Download or read book Advances in Drug Discovery Techniques written by Alan L. Harvey and published by CRC Press. This book was released on 1998-08-15 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to techniques for the discovery and evaluation of pharamcologically active compounds for therapeutic development, this book covers rational drug design, high-throughput screening, and genetic approaches to drug discovery. The authors focus on advances in the use of combinatorial chemistry and natural products, both of which support the chemical diversity for many drug screening programmes. They examine typical screening studies and their link to robotics and informatics in detail and present an overview of current progress within anitsense therapeutics. The book explores the rapid changes in drug discovery resulting from developments in molecular biology, robotics, and informatics.
