Roles of static and dynamic domains in stability and catalysis of adenylate kinase.

Protein dynamics, including conformational switching, are recognized to be crucial for the function of many systems. These motions are more challenging to study than simple static structures. Here, we present evidence suggesting that in the enzyme adenylate kinase large "hinge bending" motions closely related to catalysis are regulated by intrinsic properties of the moving domains and not by their hinges, by anchoring domains, or by remote allosteric-like regions. From a pair of highly homologous mesophilic and thermophilic adenylate kinases, we generated a series of chimeric enzymes using a previously undescribed method with synthetic genes. Subsequent analysis of the chimeras has revealed unexpected spatial separation of stability and activity control. Our results highlight specific contributions of dynamics to catalysis in adenylate kinase. Furthermore, the overall strategy and the specific mutagenesis method used in this study can be generally applied.