Browse
Submit Data
Databases
API
Help

Dataset Information

36 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Penicillin-binding protein 1 of Staphylococcus aureus is essential for growth.

ABSTRACT: pbpA, a gene encoding penicillin-binding protein (PBP) 1 of Staphylococcus aureus, was cloned in an Escherichia coli MC1061 transformant which grew on a plate containing 512 microg of vancomycin per ml. This gene encodes a 744-amino-acid sequence which conserves three motifs of PBPs, SXXK, SXN, and KTG. The chromosomal copy of pbpA could be disrupted only when RN4220, a methicillin-sensitive S. aureus strain, had additional copies of pbpA in its episome. Furthermore, these episomal copies of pbpA could not be eliminated by an incompatible plasmid when the chromosomal copy of pbpA was disrupted beforehand. Based on these observations, we concluded that pbpA is essential for the growth of methicillin-sensitive S. aureus.

SUBMITTER: Wada A

PROVIDER: S-EPMC107232 | biostudies-literature | 1998 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Penicillin-binding protein 1 of Staphylococcus aureus is essential for growth.

Wada A A Watanabe H H

Journal of bacteriology 19980501 10

pbpA, a gene encoding penicillin-binding protein (PBP) 1 of Staphylococcus aureus, was cloned in an Escherichia coli MC1061 transformant which grew on a plate containing 512 microg of vancomycin per ml. This gene encodes a 744-amino-acid sequence which conserves three motifs of PBPs, SXXK, SXN, and KTG. The chromosomal copy of pbpA could be disrupted only when RN4220, a methicillin-sensitive S. aureus strain, had additional copies of pbpA in its episome. Furthermore, these episomal copies of pbp ...[more]

PMID: 9573165

Similar Datasets

Penicillin-binding protein 2a of methicillin-resistant Staphylococcus aureus.

Project description:High-level resistance to ?-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is due to expression of penicillin-binding protein 2a (PBP2a), a transpeptidase that catalyzes cell-wall crosslinking in the face of the challenge by ?-lactam antibiotics. The activity of this protein is regulated by allostery at a site 60 Å distant from the active site, where crosslinking of cell wall takes place. This review discusses the state of knowledge on this important enzyme of cell-wall biosynthesis in MRSA.

| S-EPMC4236225 | biostudies-literature

Transcriptional analysis of the Staphylococcus aureus penicillin binding protein 2 gene.

Project description:Sequencing of the vicinity of the staphylococcal pbp2 gene and transcriptional analysis by primer extension and promoter fusions were used to show that pbp2 is part of an operon that also includes a gene with high homology to prfA of Bacillus subtilis. Two distinct promoters were identified directing transcription of pbp2 either alone or together with prfA. It was recently reported that transposon inactivation of pbp2 causes a reduction in methicillin resistance, but complementation experiments were not fully successful. We now show that introduction of the intact pbp2 gene with its two newly identified promoters into the chromosome of the transposon mutant resulted in the full recovery of high-level methicillin resistance.

| S-EPMC107690 | biostudies-literature

Kinetics of penicillin binding to penicillin-binding proteins of Staphylococcus aureus.

Project description:Reduced affinity of penicillin-binding proteins (PBPs) for binding penicillin has been proposed as a mechanism of beta-lactam antibiotic resistance in staphylococci. Penicillin binding by PBPs of three penicillin-susceptible and two penicillin-resistant strains of Staphylococcus aureus was studied in kinetic assays to determine rate constants, drug concentrations at which PBPs were bound and the relationship between concentrations that bound PBPs and concentrations that inhibited bacterial growth. PBPs 1 and 2 of the resistant strains exhibited slower acylation and more rapid deacylation than susceptible strains. In contrast PBP 4, a naturally low-affinity PBP, was modified such that it exhibited a lower rate of deacylation. The concentrations of penicillin at which modified PBPs were bound correlated with concentrations that inhibited growth of the resistant strains. Acquisition of penicillin resistance in these strains of S. aureus results, at least in part, from structural modifications affecting binding of multiple PBPs and appears to include recruitment of a non-essential PBP, PBP 4.

| S-EPMC1137153 | biostudies-other

Staphylococcus aureus penicillin-binding protein 4 and intrinsic beta-lactam resistance.

Project description:Increased levels of production of penicillin-binding protein PBP 4 correlated with in vitro acquired intrinsic beta-lactam resistance in a mutant derived from a susceptible strain of Staphylococcus aureus, strain SG511 Berlin. Truncation of the PBP 4 C-terminal membrane anchor abolished the PBP 4 content of cell membrane preparations as well as the resistance phenotype. A single nucleotide change and a 90-nucleotide deletion, comprising a 14-nucleotide inverted repeat in the noncoding pbp4 gene promoter proximal region, were the only sequence differences between the resistant mutant and the susceptible parent. These mutations were thought to be responsible for the observed overproduction of PBP 4 in the intrinsically beta-lactam-resistant mutant. The pbp4 gene was flanked upstream by the open reading frame abcA, coding for an ATP-binding cassette transporter-like protein showing similarities to eukaryotic multidrug transporters and downstream by a glycerol 3-phosphate cytidyltransferase (tagD)-like open reading frame presumably involved in teichoic acid synthesis. The abcA-pbp4-tagD gene cluster was located in the SmaI-D fragment in the S. aureus 8325 chromosome in close proximity to the RNA polymerase gene rpoB.

| S-EPMC162958 | biostudies-other

Correlation of penicillin Binding protein 2a detection with oxacillin resistance in Staphylococcus aureus and discovery of a novel penicillin binding protein 2a mutation.

Project description:We compared a rapid slide latex agglutination test (LAT; Oxoid, Basingstoke, United Kingdom) that detects penicillin binding protein 2a (PBP2a) with MicroScan conventional panels (Dade Behring, West Sacramento, CA) for detection of oxacillin resistance in Staphylococcus aureus. The PBP2a LAT demonstrated 99% agreement with MicroScan oxacillin MIC results for 388 isolates of S. aureus. All 249 oxacillin-resistant isolates gave strong positive reactions in the LAT (100% sensitivity). Three of the 139 oxacillin-susceptible isolates were also strongly positive and one was weakly positive in the LAT (97.1% specificity). The three oxacillin-susceptible isolates with strongly positive reactions were further characterized. The mecA gene was detected in all three by PCR; one isolate was determined to be resistant to oxacillin by reference broth microdilution testing (MIC, 8 microg/ml), one isolate was inducibly resistant to oxacillin (MIC of 16 microg/ml after overnight induction), and one isolate remained susceptible regardless of the method used for testing. Sequence analysis of a 2.1-kb gene fragment of the mecA gene from the susceptible isolate revealed a one-base substitution at nucleotide position 1449 which results in a Met-to-Ile change for amino acid residue 483. This amino acid substitution has not been previously reported and may be associated with a change in the function of PBP2a resulting in oxacillin susceptibility. An additional 487 isolates were tested in parallel with the both the LAT and MicroScan panels using criteria in which only strong (3 to 4+) or repeatedly weak (1 to 2+) LAT reactions were considered positive, and the results showed 99.4% agreement. The PBP2a LAT provided rapid and reliable detection of oxacillin resistance and proved a useful adjunct to the phenotypic method. Both methods provided reliable detection of oxacillin-resistant S. aureus and facilitated the discovery of a novel, functionally impaired form of PBP2a.

| S-EPMC1234091 | biostudies-literature

Penicillin-Binding Protein 3 Is Essential for Growth of Pseudomonas aeruginosa.

Project description:Penicillin-binding proteins (PBPs) function as transpeptidases, carboxypeptidases, or endopeptidases during peptidoglycan synthesis in bacteria. As the well-known drug targets for ?-lactam antibiotics, the physiological functions of PBPs and whether they are essential for growth are of significant interest. The pathogen Pseudomonas aeruginosa poses a particular risk to immunocompromised and cystic fibrosis patients, and infections caused by this pathogen are difficult to treat due to antibiotic resistance. To identify potential drug targets among the PBPs in P. aeruginosa, we performed gene knockouts of all the high-molecular-mass (HMM) PBPs and determined the impacts on cell growth and morphology, susceptibility to ?-lactams, peptidoglycan structure, virulence, and pathogenicity. Disruptions of the transpeptidase domains of most HMM PBPs, including double disruptions, had only minimal effects on cell growth. The exception was PBP3, where cell growth occurred only when the protein was conditionally expressed on an integrated plasmid. Conditional deletion of PBP3 also caused a defect in cell division and increased susceptibility to ?-lactams. Knockout of PBP1a led to impaired motility, and this observation, together with its localization at the cell poles, suggests its involvement in flagellar function. Overall, these findings reveal that PBP3 represents the most promising target for drug discovery against P. aeruginosa, whereas other HMM PBPs have less potential.

| S-EPMC5192123 | biostudies-literature

Penicillin-binding protein 4 overproduction increases beta-lactam resistance in Staphylococcus aureus.

Project description:The Staphylococcus aureus mutant strain PVI selected in vitro for methicillin resistance overexpressed penicillin-binding protein (PBP) 4. In the wild-type parent strain the pbp4 gene was separated by 419 nucleotides from a divergently transcribed abcA locus coding for an ATP-binding cassette transporter. The mutant PVI was shown to have a deletion in the pbp4-abcA promoter region that affected pbp4 transcription but not expression of abcA. Introduction of the pbp4 gene plus the mutant promoter region into different genetic backgrounds revealed that PBP 4 overproduction was sufficient to increase in vitro-acquired methicillin resistance independently of other chromosomal genes. The role of the AbcA transporter in methicillin resistance remained unknown.

| S-EPMC163484 | biostudies-other

Molecular basis for the role of Staphylococcus aureus penicillin binding protein 4 in antimicrobial resistance.

Project description:Penicillin binding proteins (PBPs) are membrane-associated proteins that catalyze the final step of murein biosynthesis. These proteins function as either transpeptidases or carboxypeptidases and in a few cases demonstrate transglycosylase activity. Both transpeptidase and carboxypeptidase activities of PBPs occur at the D-Ala-D-Ala terminus of a murein precursor containing a disaccharide pentapeptide comprising N-acetylglucosamine and N-acetyl-muramic acid-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala. Beta-lactam antibiotics inhibit these enzymes by competing with the pentapeptide precursor for binding to the active site of the enzyme. Here we describe the crystal structure, biochemical characteristics, and expression profile of PBP4, a low-molecular-mass PBP from Staphylococcus aureus strain COL. The crystal structures of PBP4-antibiotic complexes reported here were determined by molecular replacement, using the atomic coordinates deposited by the New York Structural Genomics Consortium. While the pbp4 gene is not essential for the viability of S. aureus, the knockout phenotype of this gene is characterized by a marked reduction in cross-linked muropeptide and increased vancomycin resistance. Unlike other PBPs, we note that expression of PBP4 was not substantially altered under different experimental conditions, nor did it change across representative hospital- or community-associated strains of S. aureus that were examined. In vitro data on purified recombinant S. aureus PBP4 suggest that it is a beta-lactamase and is not trapped as an acyl intermediate with beta-lactam antibiotics. Put together, the expression analysis and biochemical features of PBP4 provide a framework for understanding the function of this protein in S. aureus and its role in antimicrobial resistance.

| S-EPMC2798245 | biostudies-literature

Penicillin-binding protein PBP2a provides variable levels of protection toward different ?-lactams in Staphylococcus aureus RN4220.

Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to most ?-lactams due to the expression of an extra penicillin-binding protein, PBP2a, with low ?-lactam affinity. It has long been known that heterologous expression of the PBP2a-encoding mecA gene in methicillin-sensitive S. aureus (MSSA) provides protection towards ?-lactams, however, some reports suggest that the degree of protection can vary between different ?-lactams. To test this more systematically, we introduced an IPTG-inducible mecA into the MSSA laboratory strain RN4220. We confirm, by growth assays as well as single-cell microfluidics time-lapse microscopy experiments, that PBP2a expression protects against ?-lactams in S. aureus RN4220. By testing a panel of ten different ?-lactams, we conclude that there is also a great variation in the level of protection conferred by PBP2a. Expression of PBP2a resulted in an only fourfold increase in minimum inhibitory concentration (MIC) for imipenem, while a 32-fold increase in MIC was observed for cefaclor and cephalexin. Interestingly, in our experimental setup, PBP2a confers the highest protection against cefaclor and cephalexin-two ?-lactams that are known to have a high specific affinity toward the transpeptidase PBP3 of S. aureus. Notably, using a single-cell microfluidics setup we demonstrate a considerable phenotypic variation between cells upon ?-lactam exposure and show that mecA-expressing S. aureus can survive ?-lactam concentrations much higher than the minimal inhibitory concentrations. We discuss possible explanations and implications of these results including important aspects regarding treatment of infection.

| S-EPMC7424258 | biostudies-literature

How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function.

Project description:The expression of penicillin binding protein 2a (PBP2a) is the basis for the broad clinical resistance to the ?-lactam antibiotics by methicillin-resistant Staphylococcus aureus (MRSA). The high-molecular mass penicillin binding proteins of bacteria catalyze in separate domains the transglycosylase and transpeptidase activities required for the biosynthesis of the peptidoglycan polymer that comprises the bacterial cell wall. In bacteria susceptible to ?-lactam antibiotics, the transpeptidase activity of their penicillin binding proteins (PBPs) is lost as a result of irreversible acylation of an active site serine by the ?-lactam antibiotics. In contrast, the PBP2a of MRSA is resistant to ?-lactam acylation and successfully catalyzes the DD-transpeptidation reaction necessary to complete the cell wall. The inability to contain MRSA infection with ?-lactam antibiotics is a continuing public health concern. We report herein the identification of an allosteric binding domain--a remarkable 60 Å distant from the DD-transpeptidase active site--discovered by crystallographic analysis of a soluble construct of PBP2a. When this allosteric site is occupied, a multiresidue conformational change culminates in the opening of the active site to permit substrate entry. This same crystallographic analysis also reveals the identity of three allosteric ligands: muramic acid (a saccharide component of the peptidoglycan), the cell wall peptidoglycan, and ceftaroline, a recently approved anti-MRSA ?-lactam antibiotic. The ability of an anti-MRSA ?-lactam antibiotic to stimulate allosteric opening of the active site, thus predisposing PBP2a to inactivation by a second ?-lactam molecule, opens an unprecedented realm for ?-lactam antibiotic structure-based design.

| S-EPMC3800995 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data