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.
MeSH terms
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Amino Acid Sequence
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Bacterial Proteins / metabolism*
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Base Sequence
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Biological Evolution
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Carrier Proteins / chemistry
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Carrier Proteins / genetics*
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Carrier Proteins / metabolism
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DNA, Bacterial
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Escherichia coli / genetics*
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Escherichia coli Proteins*
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Hexosyltransferases*
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Molecular Sequence Data
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Muramoylpentapeptide Carboxypeptidase / chemistry
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Muramoylpentapeptide Carboxypeptidase / genetics*
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Muramoylpentapeptide Carboxypeptidase / metabolism
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Nucleotide Mapping
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Penicillin-Binding Proteins
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Penicillins / metabolism*
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Peptidyl Transferases*
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Sequence Alignment
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Serine-Type D-Ala-D-Ala Carboxypeptidase*
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beta-Lactamases / genetics
Substances
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Bacterial Proteins
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Carrier Proteins
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DNA, Bacterial
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Escherichia coli Proteins
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Penicillin-Binding Proteins
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Penicillins
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Peptidyl Transferases
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Hexosyltransferases
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Serine-Type D-Ala-D-Ala Carboxypeptidase
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penicillin-binding protein 4, E coli
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Muramoylpentapeptide Carboxypeptidase
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beta-Lactamases