Membranes energy transduction

Markin, V S. Thermodynamics of Membrane Energy Transduction in an Oscillating Field 24... 

Cramer W A and Knaff D B 1990 Energy Transduction in Biological Membranes (New York Springer)... 

Cells make use of many different types of membranes. All cells have a cytoplasmic membrane, or plasma membrane, that functions (in part) to separate the cytoplasm from the surroundings. In the early days of biochemistry, the plasma membrane was not accorded many functions other than this one of partition. We now know that the plasma membrane is also responsible for (1) the exclusion of certain toxic ions and molecules from the cell, (2) the accumulation of cell nutrients, and (3) energy transduction. It functions in (4) cell locomotion, (5) reproduction, (6) signal transduction processes, and (7) interactions with molecules or other cells in the vicinity. 

Cramer, W. A., and Kn2iff, D. B., 1990. Energy Transduction in Biological Membranes—A Textbook of Bioenergetics. New York Springer-Verlag, 545 pp. A textbook on bioenergetics by two prominent workers in photosyn diesis. 

W. A. Cramer and D. B. Knaff, Energy Transduction in Biological Membranes. A Textbook of Bioenergetics, Springer-Verlag, New York, 1990, pp. 353—465. 

In addition, the authors suggest that all such systems must have a semi-permeable active boundary (membrane), an energy transduction apparatus and (at least) two types of functionally interdependent macromolecular components (catalysts and records). Thus, the phenomenon of life requires not only individual self-replication and self-sustaining systems, but it also requires of such individual systems the ability to develop a characteristic, evolutionary dynamic and a historical collectivist organisation. 

We next focus on the use of fixed-site cofactors and coenzymes. We note that much of this coenzyme chemistry is now linked to very local two-electron chemistry (H, CH3", CH3CO-, -NH2,0 transfer) in enzymes. Additionally, one-electron changes of coenzymes, quinones, flavins and metal ions especially in membranes are used very much in very fast intermediates of twice the one-electron switches over considerable electron transfer distances. At certain points, the chains of catalysis revert to a two-electron reaction (see Figure 5.2), and the whole complex linkage of diffusion and carriers is part of energy transduction (see also proton transfer and Williams in Further Reading). There is a variety of additional coenzymes which are fixed and which we believe came later in evolution, and there are the very important metal ion cofactors which are separately considered below. 

Chow, W.S., Thome, S.W., Boardman, N.K. The movement of protons during energy transduction in the chloropiast thylakoid membrane. In Light Transducing Membranes (Deamer, D.W., ed.). New York, San Francisco, London Academic Press 1978, pp. 253-268... 

Skare, J.T., Ahmer, B.M., Seachord, C.L., Darveau, R.P., and Postle, K. (1993) Energy transduction between membranes. TonB, a cytoplasmic membrane protein, can be chemically cross-linked in vivo to the outer membrane receptor FepA./. Biol. Chem. 268, 16302-16308. 

Lyotropic lamellar (La) liquid crystals (LC), in a form of vesicle or planar membrane, are important for membrane research to elucidate both functional and structural aspects of membrane proteins. Membrane proteins so far investigated are receptors, substrate carriers, energy-transducting proteins, channels, and ion-motivated ATPases [1-11], The L liquid crystals have also been proved useful in the two-dimensional crystallization of membrane proteins[12, 13], in the fabrication of protein micro-arrays[14], and biomolecular devices[15]. Usefulness of an inverted cubic LC in the three-dimensional crystallization of membrane proteins has also been recognized[16]. 

Cellular membranes function as selective barriers and integral membrane protein scaffolds. Membranes allow the compartmentalization of cells, and individual organelles within cells, and are critical in energy transduction and cell signaling. In vivo membranes contain hundreds to thousands of lipid types, making characterization of particular lipid-lipid interactions challenging. 

However, any compound, even if it is chemically inert, if present at high enough concentrations in biological membranes can change those membranes properties and disrupt their functions. Consequently, membrane-associated processes like photosynthesis, energy transduction, transport in or out of the cell, enzyme activities, transmission of nerve impulses, and so on may deteriorate (see van Wezel and Opperhuizen, 1995 and literature cited therein). Since these effects seem to be primarily dependent on the space that contaminating molecules occupy in the... 

In this chapter we first describe the composition of cellular membranes and their chemical architecture— the molecular structures that underlie their biological functions. Next, we consider the remarkable dynamic features of membranes, in which lipids and proteins move relative to each other. Cell adhesion, endocytosis, and the membrane fusion accompanying neurotransmitter secretion illustrate the dynamic role of membrane proteins. We then turn to the protein-mediated passage of solutes across membranes via transporters and ion channels. In later chapters we discuss the role of membranes in signal transduction (Chapters 12 and 23), energy transduction (Chapter 19), lipid synthesis (Chapter 21), and protein synthesis (Chapter 27). 

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