title: Identification and characterization of the penicillin-binding protein 2a of Streptococcus pneumoniae and its possible role in resistance to beta-lactam antibiotics.
abstract: To further understand the role of penicillin-binding protein 2a (PBP 2a) of Streptococcus pneumoniae in penicillin resistance, we confirmed the identity of the protein as PBP 2a. The PBP 2a protein migrated electrophoretically to a position corresponding to that of PBP 2x, PBP 2a, and PBP 2b of S. pneumoniae and was absent in a pbp2a insertional mutant of S. pneumoniae. We found that the affinities of PBP 2a for penicillins were lower than for cephalosporins and a carbapenem. When compared with other S. pneumoniae PBPs, PBP 2a exhibited lower affinities for beta-lactam antibiotics, especially penicillins. Therefore, PBP 2a is a low-affinity PBP for beta-lactam antibiotics in S. pneumoniae.
authors.affiliation: Infectious Diseases Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA. Zhao_Genshi@Lilly.Com
authors.forename: G
authors.initials: G
authors.lastname: Zhao
authors.forename: T I
authors.initials: TI
authors.lastname: Meier
authors.forename: J
authors.initials: J
authors.lastname: Hoskins
authors.forename: K A
authors.initials: KA
authors.lastname: McAllister
mesh_terms: D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase / Q000378:metabolism*; D046915:Penicillin-Binding Proteins; D010453:Peptide Synthases; D010458:Peptidyl Transferases; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000378:metabolism*; D018440:beta-Lactam Resistance
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; C478699:penicillin-binding protein 2a, Streptococcus; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D010453:Peptide Synthases