A novel equation for cooperativity of the allosteric state function.
The MWC (Monod-Wyman-Changeux) allosteric model postulates concerted conformational changes between two states: the intrinsically more stable T state with relatively weak ligand binding and the R state with relatively strong ligand binding. The model distinguishes between Y¯ (the fractional occupation of the binding sites) and R¯ (the fraction of molecules in the R state). Cooperativity (measured by the Hill coefficient) has strikingly different properties for Y¯ and R¯. For the latter, cooperativity depends only on the relative affinities of the two states, not on their relative intrinsic stabilities, as demonstrated here with a simple new equation relating the Hill coefficient to R¯.
Babraham Institute, Cambridge CB22 3AT, UK. Electronic address: stuart.edelstein@unige.ch.
Stuart J
SJ
Edelstein
D000494:Allosteric Regulation; D007700:Kinetics; D008956:Models, Chemical; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*
D011506:Proteins
Hill coefficient; MWC model; allosteric; cooperativity; state function