Nucleotide sequence of a new class A beta-lactamase gene from the chromosome of Yersinia enterocolitica: implications for the evolution of class A beta-lactamases.

The nucleotide sequence has been determined of a 1400 bp fragment from the chromosome of Yersinia enterocolitica containing the gene for beta-lactamase I. An ORF of 882 bp was identified, which could code for a polypeptide of 294 amino acids, closely related to other beta-lactamases of molecular class A. Amino acids 1-30 could constitute a signal peptide. The mature protein would be 264 amino acids long with a calculated pI of 6.2. Alignment of the amino acid sequence of the class A beta-lactamases suggested the existence of two subgroups in the same class, and this is discussed in the context of the evolution of the enzymes.