Profiling of β-Lactam Selectivity for Penicillin-Binding Proteins in Streptococcus pneumoniae D39

Kocaoglu, Ozden; Tsui, Ho Ching T; Winkler, Malcolm E.; Carlson, Erin E.

doi:10.1128/aac.05142-14

Cited by 95 publications

(121 citation statements)

References 44 publications

Supporting

Mentioning

112

Contrasting

Order By: Relevance

“…With cefotaxime, R6-PBP2b is 4 ϫ 10 7 -fold less reactive than PBP2x (9). Qualitatively, the reactivities measured in vitro here and in other studies for R6 PBPs (9,10,14) are in agreement with the acylations observed in vivo (18,26).…”

supporting

confidence: 78%

“…Cefotaxime does not react significantly with PBP2b, as reported previously (12,26). This property is not general to cephalosporins, however, because nitrocefin was the most reactive drug of our panel.…”

Section: Discussionsupporting

confidence: 55%

“…This property is not general to cephalosporins, however, because nitrocefin was the most reactive drug of our panel. Examination of the structure of the different cephalosporins that fail to react with PBP2b (26,38) suggests that the nature of the R2 substituent is important. Bulky and planar substituent in position R2 appear to prevent recognition by PBP2b, whereas smaller and tetrahedral substituent seem compatible.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Calvez

Breukink

Roper

et al. 2017

Journal of Biological Chemistry

View full text Add to dashboard Cite

Edited by Gerald W. HartPneumococcus resists ␤-lactams by expressing variants of its target enzymes, the penicillin-binding proteins (PBPs), with many amino acid substitutions. Up to 10% of the sequence can be modified. These altered PBPs have a much reduced reactivity with the drugs but retain their physiological activity of crosslinking the peptidoglycan, the major constituent of the bacterial cell wall. However, because ␤-lactams are chemical and structural mimics of the natural substrate, resistance mediated by altered PBPs raises the following paradox: how PBPs that react poorly with the drugs maintain a sufficient level of activity with the physiological substrate. This question is addressed for the first time in this study, which compares the peptidoglycan crosslinking activity of PBP2b from susceptible and resistant strains with their inhibition by different ␤-lactams. Unexpectedly, the enzymatic activity of the variants did not correlate with their antibiotic reactivity. This finding indicates that some of the numerous amino acid substitutions were selected to restore a viable level of enzymatic activity by a compensatory molecular mechanism.

show abstract

supporting

confidence: 78%

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Calvez

Breukink

Roper

et al. 2017

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…This may indicate that these proteins are tolerant of side chains with diverse size and configuration (SI Table S1 and Figures S9 and 10). Intriguingly, PBP2x is a common target of the β -lactams and is often coinhibited with PBP3, 27 which was not labeled by any of the β -lactone probes. In contrast, PBP1b is among the less frequently targeted PBPs by β -lactam antibiotics, indicating that our probe library may be accessing a different region of binding space within the PBP active sites (comparisons of β -lactam and β -lactone inhibition trends in SI Figure S10).…”

Section: Resultsmentioning

confidence: 99%

Novel Electrophilic Scaffold for Imaging of Essential Penicillin-Binding Proteins in Streptococcus pneumoniae

et al. 2017

Self Cite

View full text Add to dashboard Cite

Peptidoglycan (PG) is a mesh-like heteropolymer made up of glycan chains cross-linked by short peptides and is the major scaffold of eubacterial cell walls, determining cell shape, size, and chaining. This structure, which is required for growth and survival, is located outside of the cytoplasmic membrane of bacterial cells, making it highly accessible to antibiotics. Penicillin-binding proteins (PBPs) are essential for construction of PG and perform transglycosylase activities to generate the glycan strands and transpeptidation to cross-link the appended peptides. The β-lactam antibiotics, which are among the most clinically effctive antibiotics for the treatment of bacterial infections, inhibit PBP transpeptidation, ultimately leading to cell lysis. Despite this importance, the discrete functions of individual PBP homologues have been difficult to determine. These major gaps in understanding of PBP activation and macromolecular interactions largely result from a lack of tools to assess the functional state of specific PBPs in bacterial cells. We have identified β-lactones as a privileged scaffold for the generation of PBP-selective probes and utilized these compounds for imaging of the essential proteins, PBP2x and PBP2b, in Streptococcus pneumoniae. We demonstrated that while PBP2b activity is restricted to a ring surrounding the division sites, PBP2x activity is present both at the septal center and at the surrounding ring. These spatially separate regions of PBP2x activity could not be detected by previous activity-based approaches, which highlights a critical strength of our PBP-selective imaging strategy.

show abstract

“…Such details were not observed with wide-field fluorescence microscopes before our study. Recently, we reported PBP selectivity profiling of 20 β-lactam antibiotics in E. coli and S. pneumoniae that will serve as a foundation for future probe generation 47,48 .…”

Section: Antibiotic-inspired Chemical Probesmentioning

confidence: 99%

Progress and prospects for small-molecule probes of bacterial imaging

Kocaoglu

Carlson

2016

Nat Chem Biol

Self Cite

View full text Add to dashboard Cite

Fluorescence microscopy is an essential tool for the exploration of cell growth, division, transcription and translation in eukaryotes and prokaryotes alike. Despite the rapid development of techniques to study bacteria, the size of these organisms (1–10 μm) and their robust and largely impenetrable cell envelope present major challenges in imaging experiments. Fusion-based strategies, such as attachment of the protein of interest to a fluorescent protein or epitope tag, are by far the most common means for examining protein localization and expression in prokaryotes. While valuable, the use of genetically encoded tags can result in mislocalization or altered activity of the desired protein, does not provide a readout of the catalytic state of enzymes and cannot enable visualization of many other important cellular components, such as peptidoglycan, lipids, nucleic acids or glycans. Here, we highlight the use of biomolecule-specific small-molecule probes for imaging in bacteria.

show abstract

Profiling of β-Lactam Selectivity for Penicillin-Binding Proteins in Streptococcus pneumoniae D39

Cited by 95 publications

References 44 publications

Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Novel Electrophilic Scaffold for Imaging of Essential Penicillin-Binding Proteins in Streptococcus pneumoniae

Progress and prospects for small-molecule probes of bacterial imaging

Contact Info

Product

Resources

About