title: Structure of the yeast Hst2 protein deacetylase in ternary complex with 2'-O-acetyl ADP ribose and histone peptide.
abstract: Sir2 proteins are NAD(+)-dependant protein deactylases that have been implicated in playing roles in gene silencing, DNA repair, genome stability, longevity, metabolism, and cell physiology. To define the mechanism of Sir2 activity, we report the 1.5 A crystal structure of the yeast Hst2 (yHst2) Sir2 protein in ternary complex with 2'-O-acetyl ADP ribose and an acetylated histone H4 peptide. The structure captures both ligands meeting within an enclosed tunnel between the small and large domains of the catalytic protein core and permits the assignment of a detailed catalytic mechanism for the Sir2 proteins that is consistent with solution and enzymatic studies. Comparison of the ternary complex with the yHst2/NAD(+) complex, also reported here, and nascent yHst2 structure also reveals that NAD(+) binding accompanies intramolecular loop rearrangement for more stable NAD(+) and acetyl-lysine binding, and that acetyl-lysine peptide binding induces a trimer-monomer protein transition involving nonconserved Sir2 residues.
authors: The Wistar Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors: Kehao
authors: K
authors: Zhao
authors: Xiaomei
authors: X
authors: Chai
authors: Ronen
authors: R
authors: Marmorstein
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004260:DNA Repair; D006657:Histones / Q000737:chemistry; D008239:Lysine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000502:physiology*; D056565:Sirtuin 2; D037761:Sirtuins / Q000737:chemistry* / Q000502:physiology*; D013379:Substrate Specificity
chemical_list: D006657:Histones; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; C423033:HST2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D008239:Lysine