title: Independent origins of subgroup Bl + B2 and subgroup B3 metallo-beta-lactamases.
abstract: The metallo-beta-lactamases constitute Class B in the Ambler classification of beta-lactamases and are divided into three subclasses: Bl, B2, and B3. Bayesian phylogenies of the Subclass B1 + B2 and Subclass B3 metallo-beta-lactamases and their homologs show that the beta-lactam-hydrolyzing function evolved independently within each group. In Subclass B1+B2 that function evolved about 1 billion years ago, and in Subclass B3 it evolved before the divergence of the Gram-positive and Gram-negative eubacteria, about 2 billion years ago. These results lend additional support to the proposal that the metallo-beta-lactamases should be divided into two distinct classes.
authors.affiliation: Biology Department, University of Rochester, Rochester, NY 14627, USA. drbh@mail.rochester.edu
authors.forename: Barry G
authors.initials: BG
authors.lastname: Hall
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Salipante
authors.forename: Miriam
authors.initials: M
authors.lastname: Barlow
mesh_terms: D001105:Archaea / Q000235:genetics*; D001419:Bacteria / Q000235:genetics*; D001499:Bayes Theorem; D003001:Cloning, Molecular; D019295:Computational Biology; D017931:DNA Primers; D030561:Databases, Nucleic Acid; D024881:Drug Resistance, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D015870:Gene Expression; D008957:Models, Genetic; D010802:Phylogeny; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D017931:DNA Primers; D001618:beta-Lactamases