Penicillin-binding proteins of gram-negative bacteria

Area of Science:

• Microbiology
• Biochemistry
• Evolutionary Biology

Background:

• Beta-lactam antibiotics are crucial antibacterial agents targeting bacterial cell wall synthesis.
• Penicillin-binding proteins (PBPs) are essential enzymes in peptidoglycan biosynthesis, the target of beta-lactams.
• Evidence suggests a distant evolutionary relationship between PBPs and beta-lactamase enzymes.

Purpose of the Study:

• To explore the evolutionary origins and structural relationships between PBPs and beta-lactamases.
• To understand the mechanisms of beta-lactam antibiotic resistance mediated by PBPs.

Main Methods:

• Comparative analysis of amino acid sequences of PBPs and beta-lactamases.
• Examination of three-dimensional structural similarities between low-molecular-weight PBPs and class A beta-lactamases.
• Investigation of PBP structure and function in Escherichia coli.
• Analysis of genetic alterations in PBPs conferring resistance in Neisseria gonorrhoeae.

Main Results:

• Structural similarities support a common evolutionary origin for PBPs and beta-lactamases.
• High-molecular-weight PBPs in E. coli possess distinct transglycosylase and transpeptidase domains.
• Amino acid substitutions in the transpeptidase domain of PBPs confer resistance to beta-lactam antibiotics in N. gonorrhoeae.

Conclusions:

• PBPs and beta-lactamases share a distant evolutionary heritage, evidenced by structural and sequence data.
• Understanding PBP structure is key to developing new beta-lactam antibiotics and combating resistance.
• Alterations in PBP transpeptidase domains are a significant mechanism for bacterial resistance to beta-lactam antibiotics.