SEQUENCE HOMOLOGY AND STRUCTURE PREDICTIONS OF THE CREATINE-KINASE ISOENZYMES

Comparisons of the protein sequences and gene structures of the known creatine kinase isoenzymes and other guanidino kinases revealed high h omology and were used to determine the evolutionary relationships of t he various guanidino kinases. A 'CK framework' is defined, consisting of the most conserved sequence blocks, and 'diagnostic boxes' are iden tified which are characteristic for anyone creatine kinase isoenzyme ( e.g. for vertebrate B-CK) and which may serve to distinguish this isoe nzyme from all others (e.g. from M-CKs and Mi-CKs). Comparison of the guanidino kinases by near-UV and far-UV circular dichroism further ind icates pronounced conservation of secondary structure as well as of ar omatic amino acids that are involved in catalysis.