Model peptides reveal specificity of N alpha-acetyltransferase from Saccharomyces cerevisiae.
N alpha-Acetylation is a major co-translational modification occurring at the alpha-NH2 group of eukaryotic cytosolic proteins. In order to understand better the specificity of N alpha-acetyltransferase, we used the purified enzyme from yeast (Lee, F.-J. S., Lin, L.-W., and Smith J. A. (1988) J. Biol. Chem. 263, 14948-14955) and synthetic peptides mimicking the NH2 terminus of yeast and human proteins. Alcohol dehydrogenase I-(1-24) and 8 of the 19 synthetic analogues with substitutions at the NH2-terminal residue were N alpha-acetylated with varying efficiency. Penultimate amino acid substitutions, except for proline, had little influence on N alpha-acetylation. Substitution of sequences from N alpha-acetylated proteins into the yeast sequences which cannot be N alpha-acetylated demonstrated that not only the first 3 NH2-terminal residues but also more carboxyl-terminal residues were important for determining the specificity of N alpha-acetyltransferase. Two other peptides mimicking yeast mitochondrial cytochrome c oxidase (subunit VI) and ATPase inhibitor, which are naturally non-acetylated, were efficiently acetylated. In addition, recombinant human alcohol dehydrogenase I and basic fibroblast growth factor, which are naturally N alpha-acetylated, were not acetylated post-translationally.
Department of Molecular Biology, Massachusetts General Hospital, Boston.
F J
FJ
Lee
L W
LW
Lin
J A
JA
Smith
D000107:Acetylation; D000123:Acetyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D007700:Kinetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D063206:N-Terminal Acetyltransferases; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013379:Substrate Specificity; D013482:Superoxide Dismutase / Q000378:metabolism
D010455:Peptides; D013482:Superoxide Dismutase; D000123:Acetyltransferases; D063206:N-Terminal Acetyltransferases; D010751:Phosphopyruvate Hydratase