title: Biochemical characterization of Hpa2 and Hpa3, two small closely related acetyltransferases from Saccharomyces cerevisiae.
abstract: Based on their sequences, the Saccharomyces cerevisiae Hpa2 and Hpa3 proteins are annotated as two closely related members of the Gcn5 acetyltransferase family. Here, we describe the biochemical characterization of Hpa2 and Hpa3 as bona fide acetyltransferases with different substrate specificities. Mutational and MALDI-TOF analyses showed that Hpa3 translation initiates primarily from Met-19 rather than the annotated start site, Met-1, with a minor product starting at Met-27. When expressed in Escherichia coli and assayed in vitro, Hpa2 and Hpa3 (from Met-19) acetylated histones and polyamines. Whereas Hpa2 acetylated histones H3 and H4 (at H3 Lys-14, H4 Lys-5, and H4 Lys-12), Hpa3 acetylated only histone H4 (at Lys-8). Additionally, Hpa2, but not Hpa3, acetylated certain small basic proteins. Hpa3, but not Hpa2, has been reported to acetylate D-amino acids, and we present results consistent with that. Overexpression of Hpa2 or Hpa3 is toxic to yeast cells. However, their deletions do not show any standard phenotypic defects. These results suggest that Hpa2 and Hpa3 are similar but distinct acetyltransferases that might have overlapping roles with other known acetyltransferases in vivo in acetylating histones and other small proteins.
authors.affiliation: Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Vinaya
authors.initials: V
authors.lastname: Sampath
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Liu
authors.forename: Stefan
authors.initials: S
authors.lastname: Tafrov
authors.forename: Madhusudhan
authors.initials: M
authors.lastname: Srinivasan
authors.forename: Robert
authors.initials: R
authors.lastname: Rieger
authors.forename: Emily I
authors.initials: EI
authors.lastname: Chen
authors.forename: Rolf
authors.initials: R
authors.lastname: Sternglanz
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D051046:Amino-Acid N-Acetyltransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018387:Codon, Initiator / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006609:High Mobility Group Proteins / Q000378:metabolism; D051548:Histone Acetyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D008715:Methionine / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D055503:Protein Multimerization; D011700:Putrescine / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D000596:Amino Acids; D018387:Codon, Initiator; D006609:High Mobility Group Proteins; D006657:Histones; D007527:Isoenzymes; C529112:NHP10 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013096:Spermine; D008715:Methionine; D000123:Acetyltransferases; D051046:Amino-Acid N-Acetyltransferase; C584099:Hpa3 protein, S cerevisiae; D051548:Histone Acetyltransferases; C584098:Hpa2 protein, S cerevisiae; D008239:Lysine; D013095:Spermidine; D011700:Putrescine
keywords: Acetyltransferase; Histone Acetylase; Histone Modification; Mass Spectrometry (MS); Polyamines; Translation