title: Purification and properties of penicillin-binding proteins 5 and 6 from the dacA mutant strain of Escherichia coli (JE 11191).
abstract: Penicillin-binding proteins 5 and 6 have been purified to homogeneity from the dacA mutant strain of Escherichia coli (JE 11191). Protein 6 from the mutant strain appears to be identical to that from the wild type, but protein 5 is a mutant protein which has no D-alanine carboxypeptidase activity. Moreover, the mutant protein 5 binds, but does not release, [14C]penicillin G. Correspondingly, an acyl-enzyme intermediate derived from a synthetic substrate is accumulated by the mutant protein. A comparison of the acylation site for the synthetic substrate and for penicillin G by limited proteolysis and some other properties of the mutant protein are described.
mesh_terms: D000215:Acylation; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000302:isolation & purification*; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000032:analysis* / Q000235:genetics; D006602:Hexosyltransferases; D006863:Hydrogen-Ion Concentration; D002267:Muramoylpentapeptide Carboxypeptidase; D009154:Mutation; D010400:Penicillin G / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G