Structural and functional insights into esterase-mediated macrolide resistance

Area of Science:

• Microbiology
• Structural Biology
• Biochemistry

Background:

• Macrolide antibiotics are extensively used in medicine and agriculture.
• Macrolide resistance in bacteria is a growing concern, often mediated by enzymes.
• Erythromycin esterases (Eres) are key enzymes conferring resistance through macrolactone ring cleavage.

Purpose of the Study:

• To elucidate the structural basis of macrolide resistance conferred by erythromycin esterases (Eres).
• To determine the catalytic mechanism of the Ere enzyme family.
• To investigate the diversity of active site structures within the Ere family.

Main Methods:

• X-ray crystallography to determine the 3D structures of EreC.
• In silico flexible docking studies.
• Substrate spectrum assays and analysis of residue conservation.

Main Results:

• Two distinct 3D structures of EreC, a close homolog of EreA, were determined.
• A detailed catalytic mechanism was proposed, classifying Eres as metal-independent hydrolases.
• Substrate assays and structural analysis revealed two distinct active site archetypes within the Ere family.

Conclusions:

• The structural and mechanistic insights into EreC provide a foundation for understanding Ere-mediated macrolide resistance.
• The identification of distinct active site archetypes suggests potential for developing targeted inhibitors.
• Further research into the Ere enzyme family is warranted to combat macrolide resistance.