A novel inhibitor protein of N-myristoyltransferase from Escherichia coli.
Myristoyl-CoA:protein N-myristoyltransferase (NMT) catalyzes the covalent attachment of myristate to the N-terminal of the glycine residue of various eukaryotic and viral proteins of diverse functions. Earlier, we have demonstrated that NMT activity is elevated in colon and gall bladder cancer. Attenuation of NMT activity may prove a novel therapeutic protocol for cancer. We report here a novel inhibitor protein of NMT being expressed in Escherichia coli cells containing the human NMT gene on increasing the incubation period from 5 to 24h. The inhibitor protein was purified by SP-Sepharose column chromatography, heat treatment, ammonium sulfate precipitation, and Superose 12 HR/30 FPLC column chromatography. The inhibitor protein had an apparent molecular mass of 10kDa by gel filtration. It inhibited human NMT in a concentration-dependent manner with 50% inhibition at 640+/-4.68nM. The inhibitor protein showed no direct interaction with myristoyl-CoA and demonstrated no demyristoylase or protease activity. Therefore, we conclude that the inhibitor protein acts directly on NMT.
Gowda
Sweta
S
Department of Pathology and Cancer Research Unit, Saskatchewan Cancer Agency, College of Medicine, University of Saskatchewan, S7N 4H4, Saskatoon, Sask., Canada.
Shrivastav
Anuraag
A
Selvakumar
Ponniah
P
Dimmock
Jonathan R
JR
Sharma
Rajendra K
RK
D000217:Acyltransferases / Q000037:antagonists & inhibitors*; D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D004926:Escherichia coli / Q000737:chemistry*
D004791:Enzyme Inhibitors; D000217:Acyltransferases; C050480:glycylpeptide N-tetradecanoyltransferase