Allosteric enzymes as models for chemomechanical energy transducing assemblies.

In chemomechanical energy transducing assemblies such as muscle and ATP synthase, substrates and macromolecules are locked together as partners where energy available from (or required for) a chemical transformation is exchanged with protein conformational changes. Allosteric binding proteins and enzymes are also chemomechanical energy transducers, using binding energy to generate protein conformational changes, and transduce energy in amounts almost as large as those used to drive muscle contraction and the synthesis of ATP. The recently determined structure of the F1-ATPase reveals a direct correspondence between the types of conformational changes in this transducer and simpler allosteric binding proteins and enzymes. Therefore, we can examine the structural and energetic data available on allosteric proteins to understand the linkage between ligand binding and global conformational changes in more complex energy transducing assemblies.