scholarly journals Acyltransferase activities of the high-molecular-mass essential penicillin-binding proteins

1991 ◽  
Vol 279 (2) ◽  
pp. 601-604 ◽  
Author(s):  
M Adam ◽  
C Damblon ◽  
M Jamin ◽  
W Zorzi ◽  
V Dusart ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Binding Proteins ◽  
Spectroscopic Properties ◽  
High Molecular Mass ◽  
Acyl Donor ◽  
Penicillin Binding Proteins ◽  
Cytoplasmic Membranes ◽  
Shape Determination ◽  
Hydrolysis Of

The high-molecular-mass penicillin-binding proteins (HMM-PBPs), present in the cytoplasmic membranes of all eubacteria, are involved in important physiological events such as cell elongation, septation or shape determination. Up to now it has, however, been very difficult or impossible to study the catalytic properties of the HMM-PBPs in vitro. With simple substrates, we could demonstrate that several of these proteins could catalyse the hydrolysis of some thioesters or the transfer of their acyl moiety on the amino group of a suitable acceptor nucleophile. Many of the acyl-donor substrates were hippuric acid or benzoyl-D-alanine derivatives, and their spectroscopic properties enabled a direct monitoring of the enzymic reaction. In their presence, the binding of radioactive penicillin to the PBPs was also inhibited.

scholarly journals 4-Quinolones as Noncovalent Inhibitors of High Molecular Mass Penicillin-Binding Proteins

2012 ◽  
Vol 3 (7) ◽  
pp. 592-595 ◽  
Author(s):  
Abbas G. Shilabin ◽  
Liudmila Dzhekieva ◽  
Pushpa Misra ◽  
B. Jayaram ◽  
R. F. Pratt
Keyword(s):  
Molecular Mass ◽  
Binding Proteins ◽  
High Molecular Mass ◽  
Penicillin Binding Proteins

scholarly journals All Detectable High-Molecular-Mass Penicillin-Binding Proteins Are Modified in a High-Level β-Lactam-Resistant Clinical Isolate of Streptococcus mitis

2001 ◽  
Vol 45 (7) ◽  
pp. 2075-2081 ◽  
Author(s):  
Ana Amoroso ◽  
Diego Demares ◽  
Marta Mollerach ◽  
Gabriel Gutkind ◽  
Jacques Coyette
Keyword(s):  
Molecular Mass ◽  
Clinical Isolate ◽  
Active Site ◽  
Binding Proteins ◽  
High Molecular Mass ◽  
Mosaic Structure ◽  
Kinetic Properties ◽  
Streptococcus Mitis ◽  
Penicillin Binding Proteins ◽  
High Level

ABSTRACT All detectable high-molecular-mass penicillin-binding proteins (HMM PBPs) are altered in a clinical isolate of Streptococcus mitis for which the β-lactam MICs are increased from those previously reported in our region (cefotaxime MIC, 64 μg/ml). These proteins were hardly detected at concentrations that saturate all PBPs in clinical isolates and showed, after densitometric analysis, 50-fold-lower radiotracer binding. Resistance was related to mosaic structure in all HMM PBP-coding genes, where critical region replacement was complemented not only by substitutions already reported for the closely related Streptococcus pneumoniae but also by other specific replacements that are presumably close to the active-site serine. Mosaic structure was also presumed in apbp1a-sensitive strain used for comparison, confirming that these structures do not unambiguously imply, by themselves, detectable critical changes in the kinetic properties of these proteins.

scholarly journals Functional insights into the high-molecular-mass penicillin-binding proteins of Streptococcus agalactiae revealed by gene deletion and transposon mutagenesis analysis

2021 ◽  
Author(s):  
Luchang Zhu ◽  
Prasanti Yerramilli ◽  
Layne Pruitt ◽  
Abhishek Mishra ◽  
Randall J. Olsen ◽  
...  
Keyword(s):  
Cell Wall ◽  
Molecular Mass ◽  
Binding Proteins ◽  
Bacterial Pathogen ◽  
High Molecular Mass ◽  
Isogenic Mutant ◽  
Penicillin Binding Proteins ◽  
Cell Wall Peptidoglycan ◽  
Mutant Strains ◽  
Group B

High-molecular-mass penicillin-binding proteins (PBPs) are enzymes that catalyze the biosynthesis of bacterial cell wall peptidoglycan. The Gram-positive bacterial pathogen Streptococcus agalactiae (group B streptococcus , or GBS) produces five high-molecular-mass PBPs, namely, PBP1A, PBP1B, PBP2A, PBP2B, and PBP2X. Among these, only PBP2X is essential for cell viability, whereas the other four PBPs are individually dispensable. The biological function of the four non-essential PBPs is poorly characterized in GBS. We deleted the pbp1a , pbp1b , pbp2a , and pbp2b genes individually from a genetically well-characterized serotype V GBS strain, and studied the phenotypes of the four isogenic mutant strains. Compared to the wild-type parental strain (i) none of the pbp isogenic mutant strains had a significant growth defect in THY rich medium, (ii) isogenic mutant strains Δ pbp1a and Δ pbp1b had significantly increased susceptibility to penicillin and ampicillin, and (iii) isogenic mutant strains Δ pbp1a and Δ pbp2b had significantly longer chain lengths. Using saturated transposon mutagenesis and transposon insertion site sequencing, we determined genes essential for the viability of wild-type GBS strain and each of the four isogenic pbp deletion mutant strains in THY rich medium. The pbp1a gene is essential for cell viability in the pbp2b deletion background. Reciprocally, pbp2b is essential in the pbp1a deletion background. Moreover, the gene encoding RodA, a peptidoglycan polymerase that works in conjunction with PBP2B, is also essential in the pbp1a deletion background. Together, our results suggest functional overlap between PBP1A and PBP2B-RodA complex in GBS cell wall peptidoglycan biosynthesis. IMPORTANCE High-molecular-mass penicillin-binding proteins (HMM-PBPs) are enzymes required for bacterial cell-wall biosynthesis. Bacterial pathogen group B streptococcus (GBS) produces five distinct HMM-PBPs. The biological functions of these proteins are not well characterized in GBS. In this study, we performed a comprehensive deletion analysis of genes encoding HMM-PBPs in GBS. We found that deleting certain PBP-encoding genes altered bacterial susceptibility to beta-lactam antibiotics, cell morphology, and the essentiality of other enzymes involved in cell-wall peptidoglycan synthesis. The results of our study shed new light on the biological functions of PBPs in GBS.

scholarly journals Susceptibility of Methicillin-Resistant Staphylococcus aureus to Five Quinazolinone Antibacterials

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Sara Ceballos ◽  
Choon Kim ◽  
Yuanyuan Qian ◽  
Shahriar Mobashery ◽  
Mayland Chang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Binding Proteins ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
Content Type ◽  
Penicillin Binding Proteins

ABSTRACT The in vitro activities of five quinazolinone antibacterials, compounds Q1 to Q5, were tested against 210 strains of methicillin-resistant Staphylococcus aureus (MRSA). The MIC50/MIC90 values (in μg/ml) were as follows: Q1, 0.5/2; Q2, 1/4; Q3, 2/4; Q4, 0.06/0.25; and Q5, 0.125/0.5. Several strains with high MIC values (from 8 to >32 μg/ml) for some of these compounds exhibited amino acid changes in the penicillin-binding proteins, which are targeted by these antibacterials.

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