Penicillin-binding protein 4 of Escherichia coli shows a novel type of primary structure among penicillin-interacting proteins |
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Authors: | H. Mottl P. Terpstra W. Keck |
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Affiliation: | Dept. of Biochemistry, University of Groningen, The Netherlands. |
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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. |
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Keywords: | Penicillin-binding protein β-Lactamase Sequencing |
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