Structure and function of the methionine aminopeptidases

Area of Science:

• Biochemistry
• Enzymology
• Structural Biology

Background:

• Methionine aminopeptidases (MetAPs) are essential metalloenzymes responsible for removing N-terminal methionine from proteins.
• Recent structural studies have advanced understanding of this enzyme family.
• Human MetAP is a significant target for potential anti-cancer therapeutics.

Purpose of the Study:

• To elucidate the binding modes of inhibitors and reaction products to E. coli MetAP.
• To rationalize substrate specificity and propose a catalytic mechanism for MetAP.
• To inform the design of selective enzyme inhibitors.

Main Methods:

• X-ray crystallography was used to determine the structures of E. coli MetAP bound to various ligands.
• Structure-based analysis was employed to understand enzyme-inhibitor interactions.
• Comparative analysis of active site residues and ligand interactions across enzyme families.

Main Results:

• Detailed structures revealed how bestatin-based inhibitors, transition-state analogs, and reaction products bind to E. coli MetAP.
• These findings provide a basis for understanding MetAP's substrate specificity.
• A presumed catalytic mechanism for methionine aminopeptidases was proposed.

Conclusions:

• Structural insights into E. coli MetAP inhibition and catalysis are established.
• The conservation of active site features suggests potential cross-reactivity challenges in inhibitor design.
• Targeted inhibitor design for specific MetAP family members requires careful consideration of conserved residues.