Coupling conformational

The antiparallel strand structure between residues 131 and 238 in the cytoplasmic portion of Ca -ATPase was originally designated as transduction domain the name suggested its possible role in the conformational coupling between the nucleotide binding and phosphorylation sites exposed to the cytoplasm and the Ca channel located at some distance from each other in the lipid bilayer [8,42]. The site specific mutagenesis of conserved amino acids in the P strand sector of the molecule provides support for its proposed function in conformational transitions [103,126,127,215]. 

The mechanism of the coupling between ATP hydrolysis and Ca transport is determined by the spatial relationship of the phosphorylation and ATP binding domains of the Ca -ATPase to the Ca channel involved in the translocation of calcium. Two alternative coupling mechanisms have been proposed, based on two rather different hypothetical models of the structure of the Ca -ATPase. In the conformational coupling mechanism the energy transfer between ATP hydrolysis and transport involves a mechanical coupling over long distances between... 

Machuqueiro M, Baptista AM (2006) Constant-pH molecular dynamics with ionic strength effects Protonation-conformation coupling in decalysine. J Phys Chem B 110 2927—2933. 

This preferred ground state conformation, coupled with the slither mechanism, would account for the observed stereospecificity [formation of (34c)]. The spirodienone (35) undergoes photorearrangement to form... 

We employ conformally coupled energy momentum tensor for the massless scalar field... 

Taylor This whole argument about conformational coupling has to live with the fact that there is the DT40 cell line in which all InsP3 receptors have been knocked out, and capacitative Ca2+ entry is unaffected. 

Androutsellis-Theotokis, A. and Rudnick, G. (2002) Accessibility and conformational coupling in serotonin transporter predicted internal domains. J. Neurosci. 22, 8370-8378. 

The spatial separation between the components of the electron transport chain and the site of ATP synthesis was incompatible with simple interpretations of the chemical coupling hypothesis. In 1964, Paul Boyer suggested that conformational changes in components in the electron transport system consequent to electron transfer might be coupled to ATP formation, the conformational coupling hypothesis. No evidence for direct association has been forthcoming but conformational changes in the subunits of the FI particle are now included in the current mechanism for oxidative phosphorylation. 

The observation that T0 for PVN has disappeared, as shown by examining both the damping constant and the dilatometric curve, unequivocally shows that PVN has lost its identity and that the whole copolymer behaves as an entity. The specific volume for temperatures in the amorphous region (above 60°C.) show that volume additivity for the two components is not followed, but that a contraction of about 2% has taken place. Examining the molecular models shows that one can readily entwine PEO and PVN chains. Optimum spacing is obtained with 3 ethylene oxide 1 naphthalene moiety—the complex composition Thus here, as with polyblends, the importance of conformation coupled with favorable but probably weak interactions is evident. 

The idea of conformational coupling of ATP synthesis and electron transport is especially attractive when we recall that ATP is used in muscle to carry out mechanical work. Here we have the hydrolysis of ATP coupled to motion in the protein components of the muscle. It seems reasonable that ATP should be formed as a result of motion induced in the protein components of the ATPase. Support for this analogy has come from close structural similarities of the F, ATPase P subunits and of the active site of ATP cleavage in the muscle protein myosin (Chapter 19). 

Fig. 11. Gating as a consequence of the structural interplay between two gates . (A) The present data are interpreted according to a minimal four-state sequential model in which movement of the channel intracellular gates (TM2) allows the selectivity filter to fluctuate and enter a conductive conformation that corresponds to the open state. In transit from the closed state the channel must populate an intermediate open, non-conductive state. As these states are conformationally coupled, the model predicts that the intracellular gate is unlikely to close before the selectivity filter returns to its non-conductive state. (B). The model suggests that the duration of a burst is governed by the C Cg equilibrium, occurring in the intracellular gate, while the intraburst activity (channel flicker) is determined by the Cg O transition.

Cuello, L., and Perozo, E. (2002). Conformational coupling between elements of the permeation pathway defines activation gating in K+ channels./ Gen. Physiol., in press. 

Harris, T. K., Davidson, V. L., Chen, L. Y., Mathews, F. S., and Xia, Z. X., 1994, Ionic strength dependence of the reaction between methanol dehydrogenase and cytochrome 05511 evidence of conformationally coupled electron transfer. Biochemistry 33 12600912608. 

Lanyi JK, Schobert B. Local-global conformational coupling in a heptahelical membrane protein transport mechanism from crystal structures of the nine states in the bacteriorhodopsin photocycle. Biochemistry 2004 43 3-8. 

Technologies which demonstrate environmental conformance coupled with improved material efficiencies with low energy demand combined with... 

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