Interdomain interactions in oligomeric enzymes: creation of asymmetry in homo-oligomers and role in metabolite channeling between active centers of hetero-oligomers

Interdomain interactions play an important role in the structural organization of many enzymes and the conformational flexibility of their molecules. In this review, the role of intrasubunit and intersubunit domain–domain interactions in the origins of pre-existent asymmetry of homo-oligomeric D -glyceraldehyde-3-phosphate dehydrogenase and tryptophanyl-tRNA synthetase is discussed on the basis of recent X-ray data and other available information about the properties of these and related enzymes. In addition, a novel key function of interdomain interactions is considered: their potential contribution to intramolecular channeling of intermediates between active centers located on different subunits of a hetero-oligomeric enzyme (α,β-heterodimeric carbamoyl phosphate synthetase).