       Document 0269
 DOCN  M9440269
 TI    The substrate specificity of Saccharomyces cerevisiae myristoyl-CoA:
       protein N-myristoyltransferase. Polar probes of the enzyme's
       myristoyl-CoA recognition site.
 DT    9404
 AU    Lu T; Li Q; Katoh A; Hernandez J; Duffin K; Jackson-Machelski E; Knoll
       LJ; Gokel GW; Gordon JI; Department of Molecular Biology and
       Pharmacology, Washington; University School of Medicine, St. Louis,
       Missouri 63110.
 SO    J Biol Chem. 1994 Feb 18;269(7):5346-57. Unique Identifier : AIDSLINE
       MED/94149002
 AB    Saccharomyces cerevisiae myristoyl-CoA:protein N-myristoyltransferase
       (Nmt1p) is a monomeric enzyme that is essential for vegetative growth.
       Nmt1p catalyzes the co-translational transfer of myristate from CoA to
       the amino-terminal Gly of cellular proteins in an ordered Bi Bi reaction
       mechanism that initially involves binding of myristoyl-CoA to the
       apoenzyme. Forty one fatty acid analogs were synthesized to define
       features in the acyl chain of myristoyl-CoA which are important
       determinants of its recognition by Nmt1p's acyl-CoA binding site as well
       as to help us deduce the structure of the binding site itself. These
       analogs included dicarboxylic acids, omega-nitrocarboxylic acids,
       analogs equivalent in length to C13:0-C15:0 which contain
       electronegative halogens at their omega-termini, hydroxytetradecanoic
       acids with hydrogen replaced by OH from C3 to C13, and
       azidophenyl-containing fatty acids with the linear azide unit attached
       either meta or para to phenyl and with variations in the length of their
       methylene chains. These compounds were converted to their CoA
       derivatives using Pseudomonas acyl-CoA synthetase and then surveyed as
       substrates for purified Nmt1p in an in vitro assay system that included
       an octapeptide derived from residues 1-8 of the human immunodeficiency
       virus Pr55gag polyprotein precursor. The results suggest that the
       myristoyl-CoA binding site contains a conical-shaped receptor that
       interacts with the omega-terminus of the bound acyl chain of acyl-CoAs.
       The acuteness of this cone determines the enzyme's capacity to
       accommodate steric bulk at the omega-terminus as well as Nmt1p's
       sensitivity to the distance between the eclipsed C5-C6 bond of a bound
       acyl chain and its omega-terminus. The activity profile of the various
       analog-CoAs also indicates that the enzyme's myristoyl-CoA binding site
       can accommodate fatty acid analogs with marked increases in polarity at
       their omega-terminus (compared to C14:0) as long as their chain length
       is equivalent to that of myristate.
 DE    Acyl Coenzyme A/*METABOLISM  Acyltransferases/*METABOLISM  Binding Sites
       Coenzyme A Synthetases/METABOLISM  Comparative Study  Fatty Acids,
       Nonesterified/CHEMISTRY/CHEMICAL SYNTHESIS/  *METABOLISM  Indicators and
       Reagents  Kinetics  Models, Molecular  Molecular Structure  Myristic
       Acids/*METABOLISM  Pseudomonas/ENZYMOLOGY  Saccharomyces
       cerevisiae/*ENZYMOLOGY  Substrate Specificity  Support, Non-U.S. Gov't
       Support, U.S. Gov't, P.H.S.  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

