Conformational coupling mechanism

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... 

What is chemiosmotic coupling Two mechanisms, the chemiosmotic mechanism and the conformational coupling mechanism, have been proposed to explain the coupling of electron transport and ATP production. 

What is conformational coupling In the conformational coupling mechanism, the proton gradient is indirectly related to ATP production. Recent evidence appears to show that the effect of the proton gradient is not the formation of ATP but the release of tightly bound ATP from the synthase as a result of the conformational change. 

The Coupling Mechanism ATP Hydrolysis Drives Conformation Changes in the Myosin Heads... 

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... 

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 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). 

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. 

The iodane 27 is in equilibrium with its conformational isomer 27 Coupling between the apical and equatorial ligand should result in 25 from 27 and 26 from 11 . The ligand coupling mechanism can be regarded as a pseudo-intramolecular (unimolecular) variant of the (bimolecular) SnVtt pathway, as discussed in the theoretical section (Fig. 3). 

---