An evolutionarily conserved allosteric site modulates beta-lactamase activity

Area of Science:

• Biochemistry
• Structural Biology
• Drug Discovery

Background:

• Antibiotic resistance, particularly beta-lactamase mediated resistance, is a growing global health threat.
• Conventional therapies targeting enzyme active sites face declining efficacy, necessitating alternative strategies like allosteric inhibition.

Purpose of the Study:

• To investigate the role of the evolutionarily conserved PWP triad in the allosteric regulation of TEM-1 beta-lactamase activity.
• To explore the PWP triad as a potential target for developing novel inhibitors against beta-lactamase-mediated resistance.

Main Methods:

• Site-directed mutagenesis of the PWP triad in TEM-1 beta-lactamase.
• Structural and dynamic analyses of mutant enzymes using biophysical techniques.
• Sequence and structure conservation analyses across class A beta-lactamases.

Main Results:

• Point mutations in the PWP triad altered the enzyme's global structure, increasing dynamics and decreasing stability.
• Mutant enzymes exhibited reduced activity, correlating with a less compact hydrophobic core around the allosteric site.
• The PWP triad was identified as a conserved motif unique to class A beta-lactamases, directly interacting with the allosteric site.

Conclusions:

• The PWP triad is a critical allosteric regulator of TEM-1 beta-lactamase activity.
• Targeting the PWP triad offers a promising strategy for designing selective inhibitors against beta-lactamase-mediated resistance.