Yeast Genetics and Molecular Biology 2000
University of Washington
Seattle, Washington USA
July 2000

Name: Polevoda, Bogdan
Mailing Address: Dept.of Biochemistry & Biophys, University of Rochester, 601 Elmwood Ave., Rochester, NY 14642, USA
Email Address: Bogdan_Polevoda@urmc.rochester.edu
Phone & FAX numbers: 716-275-3329 & 716-271-2683

#047

Identification and specificities of N -terminal acetyltransferases from Saccharomyces cerevisiae.
Bogdan Polevoda (1), Joakim Norbeck (2), Randy J. Arnold (3), Hikaru Takakura (4), Hisashi Hirano (5), Anders Blomberg (2), James P. Reilly (3), Fred Sherman (1)
(1) Dept. of Biochemistry & Biophys, University of Rochester, 601 Elmwood Ave., Rochester, NY 14642, USA; (2) Dept. of Cell and Molecular Biology and Microbiology, Goteborg Universtity, S-413 90 Goteborg SWEDEN; (3) Dept. of Chemistry, Indiana University, Bloomington, IN 47405 USA; (4) Takara Shuzo Co. Ltd., Biotechnology Research Laboratory, Otsu, Shiga, 520-21 JAPAN; (5) Yokohama City University, Kihara Institute for Biological Research, Totsuka, Yokohama 244-0813, JAPAN

N-terminal acetylation can occur cotranslationally on the initiator methionine residue, or on the penultimate residue if the methionine is cleaved. We have investigated the three yeast NATs (N-terminal acetyltransferases), Ard1p/Nat1p, Nat3p and Mak3p. Ard1p, Nat3p and Mak3p are significantly related to each other by amino acid sequence. Mutants deleted in any one of these NAT genes were viable, but some exhibited diminished mating efficiency, and reduced growth at 37°C and on glycerol medium and NaCl-containing media. The substrate specificities were determined in vivo by examining acetylation of 148 proteins in each of the following deleted strains: Ard1p/Nat1p, responsible for acetylating subclasses of proteins with Ser-, Ala-, Gly- and Thr- termini (NatA type); Nat3p, responsible for acetylating of proteins with Met-Glu- and Met-Asp- and a subclass of Met-Asn- termini (NatB type); Mak3p, responsible for acetylating of proteins with Met-Ile, Met-Leu and some Met-Phe-termini (NatC type). In addition, a special subclass of substrates with Ser-Glu-Phe-, Ser-Asp- and certain related N-termini required all three NATs for acetylation (NatD type). Also, these results along with previously published studies revealed that penultimate Asn, Asp, Gln and Glu residues are usually required for acetylation of subclasses of the NatA and NatB substrates, whereas penultimate Arg, His and Pro residues interfere with N-terminal acetylation.

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