Thermodynamics and Mesomechanics of Nanostructural Transitions in Biological Membranes as Liquid Crystals
نویسنده
چکیده
Biological membranes play a key role in structural-functional organization of any cells. Membranes constitute 65% of the cell dry weight, of them 40% belong to lipids and 60% to simple and conjugate proteins. Membranes separate cell into functional units (divisions); as a result, cell operates as a complicated factory in miniature. Besides, membranes integrate the operation of cell as a whole. Cell is an open system. It steadily exchanges weight, energy and information with the environment. This process also involves the biological (cell) membranes. All biological membranes are liquid-crystalline structures. They consist of phospholipids bilayer, with simple and conjugate proteins immersed in it. These are various membranebound enzymes, transmembrane carriers (of glucose, Na+ and K+ ions, and others), and hormone receptors that serve as signal mechanisms of the cell. Structure-forming bonds in liquid crystals are represented by covalent and hydrogen bonds, hydrophobic and electrostatic interactions. These are the low-energy binding: covalent bonds — 50-100 kcal/mol, hydrogen bonds — about 6 kcal/mol. Between fatty acid tails of phospholipids there is a large amount of water dipoles. Such structure of the membrane provides high mobility of its structural components relative to each other. Membranes are reinforced by cholesterol molecules, which strengthen the hydrophobic interactions. Such membrane responds to external action as a cooperative system.
منابع مشابه
Mesomechanics and Thermodynamics of Nanostructural Transitions in Biological Membranes Under the Action of Steroid Hormones
متن کامل
Capillary models for liquid crystal fibers, membranes, films, and drops
This paper presents an overview of the capillary modeling science of nematic liquid crystals and its applications to the stability, structure, and shape of films, membranes, fibers, and drops. Liquid crystals are anisotropic viscoelastic materials possessing long range orientational order, and hence these models are relevant to the capillary science of anisotropic soft matter. A systematic mult...
متن کاملThermodynamic characterization of bilayer- nonbilayer phase transitions of phospholipid membranes
We determined thermodynamic properties of phase transitions between bilayer and nonbilayer for phosphatidylcholines with saturated hydrophobic chains (C18:0-PC, O-C18:0PC) and phosphatidylethanolamines with unsaturated ones (C18:1(cis)-PE, C18:1(trans)-PE) by means of calorimetry under ambient pressure and optical measurements under high pressure. The thermodynamic quantities of the transitions...
متن کاملInsights into Glass Formation and Glass Transition in Supercooled Liquids, by Study of Related Phenomena in Crystals
We divide glass and viscous liquid sciences into two major research areas, the first dealing with how to avoid crystals and so access the viscous liquid state, and the second dealing with how liquids behave when no crystals form. We review some current efforts to elucidate each area, looking at strategies for vitrification of monatomic metals in the first, and the origin of the property “fragil...
متن کاملAtomic Force Microscopy Application in Biological Research: A Review Study
Atomic force microscopy (AFM) is a three-dimensional topographic technique with a high atomic resolution to measure surface roughness. AFM is a kind of scanning probe microscope, and its near-field technique is based on the interaction between a sharp tip and the atoms of the sample surface. There are several methods and many ways to modify the tip of the AFM to investigate surface properties, ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2012