Specificity for inhibitors of metal-substituted methionine aminopeptidase.
Methionine aminopeptidases (MetAPs) have been studied in vitro as Co(II) enzymes, but their in vivo metal remains to be defined. While activation of Escherichia coli MetAP (EcMetAP1) by Co(II), Mn(II), and Zn(II) was detectable by a colorimetric Met-S-Gly-Phe assay, significant activation by Ni(II) was shown in a fluorescence Met-AMC assay, in addition to Co(II) and Mn(II) activation. When tested on the metal-substituted EcMetAP1s, a few inhibitors that we obtained recently from a random screening on Co-EcMetAP1 either became much weak or lost activity on Mn- or Zn-EcMetAP1, although they kept inhibitory activity on Ni-EcMetAP1. A couple of peptidic inhibitors and the methionine mimetic (3R)-amino-(2S)-hydroxyheptanoic acid (AHHpA, 6) maintained moderate activities on Co-, Mn-, Zn-, and Ni-EcMetAP1s. Our results clearly demonstrate that the metal-substitution has changed the enzyme specificity for substrates and inhibitors. Therapeutic applications call for inhibitors specific for MetAP with a physiologically relevant metal at its active site.
Li
Jing-Ya
JY
Chinese National Center for Drug Screening, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 189 Guo-Shou-Jing Road, Shanghai 201203, China.
Chen
Ling-Ling
LL
Cui
Yong-Mei
YM
Luo
Qun-Li
QL
Li
Jia
J
Nan
Fa-Jun
FJ
Ye
Qi-Zhuang
QZ
D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D008670:Metals / Q000378:metabolism*; D063208:Methionyl Aminopeptidases; D015394:Molecular Structure; D013379:Substrate Specificity
D001426:Bacterial Proteins; D002413:Cations, Divalent; D004791:Enzyme Inhibitors; D008670:Metals; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases