title: Penicillin-binding protein 2x of Streptococcus pneumoniae: enzymic activities and interactions with beta-lactams.
abstract: The high-molecular-mass penicillin-binding protein (PBP) 2x, one of the primary targets of beta-lactam antibiotics in Streptococcus pneumoniae, has been produced as a soluble form and purified in large amounts. It has been shown to catalyse hydrolysis and transfer reactions with different ester and thiolester substrates and its catalytic behaviour was often similar to that of the soluble DD-peptidase from Streptomyces R61. This provided an easy method to monitor the activity of the PBP. For the first time, a reliable kinetic study of the interaction between a lethal target and beta-lactam antibiotics has been performed. Characteristic kinetic parameters were obtained with different beta-lactam compounds. These results not only validated the mechanism established with non-essential extracellular enzymes, but will also constitute the basis for comparative studies of the low-affinity variants from penicillin-resistant strains.
authors.affiliation: Laboratoire d'Enzymologie, Université de liège, Sart Tilman, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Jamin
authors.forename: C
authors.initials: C
authors.lastname: Damblon
authors.forename: S
authors.initials: S
authors.lastname: Millier
authors.forename: R
authors.initials: R
authors.lastname: Hakenbeck
authors.forename: J M
authors.initials: JM
authors.lastname: Frère
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002439:Cefotaxime / Q000378:metabolism; D002852:Chromatography, Ion Exchange; D006602:Hexosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D007525:Isoelectric Focusing; D007700:Kinetics; D009097:Multienzyme Complexes / Q000302:isolation & purification / Q000378:metabolism*; D002267:Muramoylpentapeptide Carboxypeptidase; D010400:Penicillin G / Q000378:metabolism; D046915:Penicillin-Binding Proteins; D010455:Peptides / Q000378:metabolism; D010458:Peptidyl Transferases / Q000302:isolation & purification / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000201:enzymology*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D009097:Multienzyme Complexes; D046915:Penicillin-Binding Proteins; D010455:Peptides; C072223:PBP 2x protein, Streptococcus; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D002439:Cefotaxime; D010400:Penicillin G