Title: Sequences of the active-site peptides of three of the high-Mr penicillin-binding proteins of Escherichia coli K-12. | Journal: Proceedings of the National Academy of Sciences of the United States of America. 1985 Apr;82(7):1999-2003 | Authors: Keck W, Glauner B, Schwarz U, Broome-Smith JK, Spratt BG. | Abstract: The amino acid compositions of the radioactive peptides obtained from trypsin digestion of [14C]benzylpenicillin-labeled penicillin-binding proteins (PBPs) 1A, 1B, and 3 of Escherichia coli have been obtained. Complete digestion of these peptides with a combination of aminopeptidase M and carboxypeptidase Y showed that benzylpenicillin was bound to a serine residue in each of these proteins. Comparison of the compositions of the penicillin-labeled peptides with the complete amino acid sequences of PBPs 1A, 1B, and 3 showed that the acylated serine occurs near the middle of each of the proteins, within the conserved sequence Gly-Ser-Xaa-Xaa-Lys-Pro. The sequence around the acylated serine of these high Mr PBPs shows little similarity to that around the acylated serine of the low-Mr PBPs (D-alanine carboxypeptidases) or of the class A or class C beta-lactamases, except that in all of these enzymes which interact with penicillin the acylated serine residue occurs within the sequence Ser-Xaa-Xaa-Lys. | See full PubMed entry: http://www.ncbi.nlm.nih.gov/pubmed/3920658 |
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