title: Purification and partial characterization of a penicillin-binding protein from Mycobacterium smegmatis.
abstract: Penicillin-binding proteins (PBPs), although characterized from several organisms, have so far not been studied in mycobacteria. The present study is the first characterization of a PBP from Mycobacterium smegmatis. The PBP was purified by solubilization of the membranes with Triton X-100 and successive chromatography of the solubilized proteins on ampicillin-linked CH Sepharose 4B and DE-52. The purified PBP (M(r), 49,500) catalyzed a model transpeptidase reaction with the tripeptide acetyl2-L-Lys-D-Ala-D-Ala as the substrate and Gly-Gly as the acceptor. The transpeptidase activity was inhibited by 50% at a benzylpenicillin concentration of 1.8 x 10(-7) M, which was similar to the concentration (1.1 x 10(-7) M) of benzylpenicillin required to saturate to 50% this PBP. Of several antibiotics tested, the concentration of antibiotic required to inhibit [35S]penicillin binding by 90% was found to be the lowest for cefoxitin and Sch 34343.
authors.affiliation: Department of Chemistry, Bose Institute, Calcutta, India.
authors.forename: J
authors.initials: J
authors.lastname: Basu
authors.forename: R
authors.initials: R
authors.lastname: Chattopadhyay
authors.forename: M
authors.initials: M
authors.lastname: Kundu
authors.forename: P
authors.initials: P
authors.lastname: Chakrabarti
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002845:Chromatography; D006602:Hexosyltransferases; D007769:Lactams; D008969:Molecular Sequence Data; D002267:Muramoylpentapeptide Carboxypeptidase / Q000302:isolation & purification / Q000378:metabolism*; D009161:Mycobacterium / Q000201:enzymology* / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism*; D010458:Peptidyl Transferases
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D007769:Lactams; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase