An evolutionary classification of the metallo-beta-lactamase fold proteins.

All the detectable metallo-beta-lactamase fold proteins were identified in the publicly available sequence databases and complete genome sequences using iterative profile searches with the PSI-BLAST program and motif searches with position specific weight matrices. The catalytic site/mechanism and the corresponding structural elements were characterized for these proteins based on the available structure of the Bacillus zinc-dependent beta-lactamase. Based on pair-wise sequence and phylogenetic analysis an evolutionary classification for enzymes of this fold was developed and discussed in terms of implications for substrate specificity. Finally, some predicted inactive members which have been recruited for non-enzymatic functions such as microtubule binding in a cytoskeletal MAP1 are described.