Sequences of the Active-Site Peptides of Three of the High-MrPenicillin-Binding Proteins of Escherichia coli K-12

The amino acid compositions of the radioactive peptides obtained from trypsin digestion of [14C]benzyl-penicillin-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 carboxype...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1985-04, Vol.82 (7), p.1999-2003
Main Authors: Keck, Wolfgang, Glauner, Bernd, Schwarz, Uli, Broome-Smith, Jenny K., Spratt, Brian G.
Format: Article
Language:English
Subjects:
Amino acids
Antibiotics
Biochemistry
Cell walls
Enzymes
Escherichia coli
Penicillin
Phosphates
Plasmids
Teeth
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Summary:The amino acid compositions of the radioactive peptides obtained from trypsin digestion of [14C]benzyl-penicillin-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 MrPBPs shows little similarity to that around the acylated serine of the low-MrPBPs (D-alanine carboxypeptidases) or of the class A or class C β -lactamases, except that in all of these enzymes which interact with penicillin the acylated serine residue occurs within the sequence Ser-Xaa-Xaa-Lys.
ISSN:0027-8424