Membrane Biophysics

Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

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.

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.

This book highlights recent advances in and diverse techniques for exploring the plasma membrane’s structure and function. It starts with two chapters reviewing the history of membrane research and listing recent advances regarding membrane structure, such as the semi-mosaic model for red blood cell membranes and the protein layer-lipid-protein island model for nucleated tissue cell membranes. It subsequently focuses on the localization and interactions of membrane components, dynamic processes of membrane transport and transmembrane signal transduction. Classic and cutting-edge techniques (e.g. high-resolution atomic force microscopy and super-resolution fluorescence microscopy) used in biophysics and chemistry are presented in a very comprehensive manner, making them useful and accessible to both researchers in the field and novices studying cell membranes. This book provides readers a deeper understanding of the plasma membrane’s organization at the single molecule level and opens a new way to reveal the relationship between the membrane’s structure and functions, making it essential reading for researchers in various fields.

This volume provides recent advances in the field of biophysics of membrane proteins. Chapters are divided into several parts: detailing biochemistry and functional analysis, experimental and theoretical structural determinations, membrane protein dynamics, and conformation studies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Biophysics of Membrane Proteins: Methods and Protocols aims to provide comprehensive protocols with notes to help further the understanding of key membrane protein structure and function for students, academics, and industrial researchers.

Starting from a comprehensive quantum mechanical description, this book introduces the optical (IR, Raman, UV/Vis, CD, fluorescence and laser spectroscopy) and magnetic resonance (1D and 2D-NMR, ESR) techniques. The book offers a timely review of the increasing interest in using spin-label ESR as an alternative structural technique for NMR or X-ray diffraction. Future aspects are treated as well, but only as an illustration of the progress of ESR in this field.

Equations of Membrane Biophysics provides an introduction to the relevant principles of thermodynamics, kinetics, electricity, surface chemistry, electrochemistry, and other mathematical theorems so that the quantitative aspects of membrane phenomena in model and biological systems could be described. The book begins by introducing several phenomena that arise across membranes, both artificial and biological, when different driving forces act across them. This is followed by separate chapters on thermodynamic principles related to properties of dilute aqueous electrolyte solutions along with a review of the principles of electrostatics, electrochemical principles, Fick's laws of diffusion, and the rate theory of diffusion; the quantitative aspects of the electrochemistry of solutions and membranes, and the quantitative relations between charges and electrostatic potentials related to surfaces and interfaces; and membrane theories pertaining to electrical potentials arising across a variety of membranes. Subsequent chapters deal with steady-state thermodynamic approaches to several transport phenomena in membranes; tissue impedance, cable theory, and Hodgkin-Huxley equations; and fluctuation analysis of the electrical properties of the membrane.

This book summarizes the current status of research on bilayer lipid membranes (planar lipid bilayers and spherical liposomes). In addition to describing the properties of lipid bilayers and examining biomembrane phenomena, the book has two other objectives. The first is to present practical methods for the formation and study of lipid bilayers with either aqueous or metal-lipid bilayer interfaces. The second aim is to treat planar lipid bilayers as a new type of interfacial adsorption phenomena. The first nine chapters cover properties of biomembranes, basic principles of membrane biophysics, transport, electrochemistry, physiology, bioenergetics, and photobiology. Chapter 10 presents the following topics: lipid bilayers in medicine, supported lipid bilayers as sensors, a short discussion of liposomes, and solar energy transduction via semiconductor septum photovoltaic cells based on natural photosynthesis.