Structural insight into the subclass B1 metallo-β-lactamase AFM-1

Area of Science:

• Biochemistry
• Structural Biology
• Microbiology

Background:

• Metallo-beta-lactamases (MBLs) are key enzymes driving antibiotic resistance in bacteria.
• AFM-1, an MBL from Alcaligenes faecalis, shares homology with NDM-1 but exhibits different substrate affinities.
• The structural basis for AFM-1's substrate binding and catalytic activity remains largely uncharacterized.

Purpose of the Study:

• To elucidate the high-resolution structure of the AFM-1 metallo-beta-lactamase.
• To investigate the structural determinants underlying AFM-1's substrate binding and hydrolytic activity.
• To provide a molecular understanding of AFM-1's role in antibiotic resistance.

Main Methods:

• X-ray crystallography was employed to determine the high-resolution structure of AFM-1.
• Comparative structural analysis was performed between AFM-1 and NDM-1.
• Molecular modeling and analysis of active site and substrate-binding pocket features were conducted.

Main Results:

• The high-resolution structure of AFM-1 reveals a binuclear zinc active center, similar to NDM-1.
• AFM-1 possesses a smaller substrate-binding pocket compared to NDM-1.
• Mutations in the Loop3 region of AFM-1 create a hydrophobic patch that enhances substrate binding.

Conclusions:

• The structural insights into AFM-1 provide a molecular basis for its substrate affinity and hydrolytic capabilities.
• Understanding the structural differences between AFM-1 and NDM-1 is crucial for developing novel inhibitors.
• These findings offer a theoretical foundation for combating drug resistance mediated by B1 MBLs.