[The structural-functional organization of the diphtheria toxin].

The present data on the structure and functional features of diphtheria toxin, the main pathogenic factor of diphtheria infection, have been described. Information on the primary and secondary structures and X-ray analysis of this protein is presented and discussed. The structures of catalytic, transmembrane and receptor-binding domains of diphtheria toxin have been considered in detail and the functional roles of some amino-acid residues of these domains have been analyzed.