Penicillin-binding protein 4 of Escherichia coli shows a novel type of primary structure among penicillin-interacting proteins

1 March 1991

journal article
Published by Oxford University Press (OUP) in FEMS Microbiology Letters

Vol. 78 (2-3) , 213-220
https://doi.org/10.1016/0378-1097(91)90160-c

Abstract

The nucleotide sequence of a 1884 bp DNA fragment of E. coli, carrying the gene dacB, was determined. The DNA codes for penicillin-binding protein 4 (PBP4), an enzyme of 477 amino acids, being involved as a DD-carboxypeptidase-endopeptidase in murein metabolism. The enzyme is translated with a cleavable signal peptide of 20 amino acids, which was verified by sequencing the amino-terminus of the isolated protein. The characteristic active-site fingerprints SXXK, SXN and KTG of class A beta-lactamases and penicillin-binding proteins were located in the sequence. On the basis of amino acid alignments we propose, that PBP4 and class A beta-lactamases share a common evolutionary origin but PBP4 has acquired an additional domain of 188 amino acids in the region between the SXXK and SXN elements.

Keywords

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