STRUCTURE-FUNCTION-RELATIONSHIPS IN MULTIENZYME COMPLEXES

The structures and the mechanisms of functioning of multienzyme comple xes of the 2-ketoacid dehydrogenase family are considered. It is assum ed that identical protein subunits form identical interfaces with thei r neighbors and hence have identical surroundings in multienzyme compl exes capable of self-assembly. Dividing the subunits into different co nformational classes, one can position the peripheral components on th e skeleton in a way allowing symmetry of the entire complex. The numbe r of conformational classes is determined by the skeleton architecture and symmetry considerations. This structural analysis has some implic ations for the reaction mechanisms of multienzyme complexes. Some spec ific cases are discussed.