Inhibition of monometalated methionine aminopeptidase: inhibitor discovery and crystallographic analysis.
Two divalent metal ions are commonly seen in the active-site cavity of methionine aminopeptidase, and at least one of the metal ions is directly involved in catalysis. Although ample structural and functional information is available for dimetalated enzyme, methionine aminopeptidase likely functions as a monometalated enzyme under physiological conditions. Information on structure, as well as catalysis and inhibition, of the monometalated enzyme is lacking. By improving conditions of high-throughput screening, we identified a unique inhibitor with specificity toward the monometalated enzyme. Kinetic characterization indicates a mutual exclusivity in binding between the inhibitor and the second metal ion at the active site. This is confirmed by X-ray structure, and this inhibitor coordinates with the first metal ion and occupies the space normally occupied by the second metal ion. Kinetic and structural analyses of the inhibition by this and other inhibitors provide insight in designing effective inhibitors of methionine aminopeptidase.
Huang
Min
M
High Throughput Screening Laboratory, University of Kansas, Lawrence, Kansas 66045, USA.
Xie
Sheng-Xue
SX
Ma
Ze-Qiang
ZQ
Huang
Qing-Qing
QQ
Nan
Fa-Jun
FJ
Ye
Qi-Zhuang
QZ
D000626:Aminopeptidases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D001051:Apoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry; D002413:Cations, Divalent; D003035:Cobalt; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000201:enzymology; D006834:Hydrazines / Q000737:chemistry*; D007501:Iron; D008345:Manganese; D008670:Metals; D063208:Methionyl Aminopeptidases; D009532:Nickel; D011485:Protein Binding; D011758:Pyrroles / Q000737:chemistry*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D054852:Small Molecule Libraries
D001051:Apoenzymes; D002413:Cations, Divalent; D006834:Hydrazines; D008670:Metals; D011758:Pyrroles; D011994:Recombinant Proteins; D054852:Small Molecule Libraries; C525469:pyrrolo(2,3-a)isoquinoline-2-carboxylic acid hydrazide; D003035:Cobalt; D008345:Manganese; D009532:Nickel; D007501:Iron; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases