Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
1995-1-4
pubmed:abstractText
N-Myristyl transferase (Nmt) catalyzes attachment of myristate onto the N terminus of suitable proteins. In order to identify amino acids important for catalytic functions, human Nmt and mutants representing all six conserved cysteine and histidine residues (Cys-169, Cys-214, His-131, His-171, His-218, and His-293) were expressed in Escherichia coli and analyzed for their ability to bind and transfer myristic acid. N-Terminal histidine-tagged fusion proteins displayed varying abilities to form an association with radiolabeled myristic acid indicative of an acyl-enzyme intermediate. When co-expressed with an acceptor substrate protein, pp60v-src, the mutants showed differential incorporation of radiolabeled myristic acid into v-Src protein. In vitro experiments monitoring transfer of myristyl CoA to a peptide homologous to the N terminus of pp60 v-src gave results similar to those obtained in vivo. Our studies showed that mutation at Cys-169, His-171, and especially His-293 interfered with formation of an acyl-enzyme intermediate, while human Nmts containing mutations at Cys-169, His-218, or His-293 showed greatly attenuated abilities to form acylated product. We propose a model for the Nmt reaction mechanism in which Cys-169 serves as the fatty acid attachment site for a covalent myristyl enzyme intermediate, while His-171 acts as a general acid/base and His-293 as a specific acid/base during acyl-enzyme intermediate formation. His-218 could then act as an acid or base needed to catalyze transfer of the acyl group from the acyl-enzyme intermediate to a polypeptide substrate. This working model will be useful for the design of regulators of Nmt function.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
269
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
30888-92
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Fatty acyl transfer by human N-myristyl transferase is dependent upon conserved cysteine and histidine residues.
pubmed:affiliation
Cell Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't