Understanding the selectivity of fumagillin for the methionine aminopeptidase type II

Area of Science:

• Biochemistry
• Enzymology
• Drug Discovery

Background:

• Fumagillin is an antiangiogenic drug with known selectivity for methionine aminopeptidase type II (MetAP-II).
• Methionine aminopeptidase type I (MetAP-I) is structurally similar to MetAP-II, making the selectivity of fumagillin a key question.
• Understanding this selectivity is crucial for developing targeted therapies.

Purpose of the Study:

• To elucidate the molecular basis for fumagillin's selective inhibition of MetAP-II over MetAP-I.
• To investigate the structural and dynamic differences between MetAP-I and MetAP-II active sites concerning fumagillin binding.

Main Methods:

• Homology modeling was used to create a structural model for human MetAP-I.
• Molecular dynamics simulations were performed on MetAP-I (with and without fumagillin) and MetAP-II.
• Comparative analysis of active site flexibility and residue conformations.

Main Results:

• MetAP-I exhibits increased flexibility in the active site histidine residue targeted by fumagillin.
• MetAP-I active site residues, particularly the fumagillin-binding histidine, are less likely to adopt a reactive conformation compared to MetAP-II.
• These dynamic differences explain fumagillin's preferential binding to MetAP-II.

Conclusions:

• The differential flexibility and conformational probabilities of active site residues in MetAP-I and MetAP-II explain fumagillin's selectivity.
• This study provides a molecular rationale for the targeted action of fumagillin against MetAP-II.
• Findings contribute to the rational design of more selective enzyme inhibitors.