| Structural highlights
Function
[HST2_YEAST] NAD-dependent histone deacetylase that is involved in nuclear silencing events. Derepresses subtelomeric silencing and increases repression in nucleolar (rDNA) silencing. Its function is negatively regulated by active nuclear export.[1] [2] [3] [4] [5]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Sir2 enzymes are broadly conserved from bacteria to humans and have been implicated to play roles in gene silencing, DNA repair, genome stability, longevity, metabolism, and cell physiology. These enzymes bind NAD(+) and acetyllysine within protein targets and generate lysine, 2'-O-acetyl-ADP-ribose, and nicotinamide products. To provide structural insights into the chemistry catalyzed by Sir2 proteins we report the high-resolution ternary structure of yeast Hst2 (homologue of Sir two 2) with an acetyllysine histone H4 peptide and a nonhydrolyzable NAD(+) analogue, carba-NAD(+), as well as an analogous ternary complex with a reaction intermediate analog formed immediately after nicotinamide hydrolysis, ADP-ribose. The ternary complex with carba-NAD(+) reveals that the nicotinamide group makes stabilizing interactions within a binding pocket harboring conserved Sir2 residues. Moreover, an asparagine residue, N116, strictly conserved within Sir2 proteins and shown to be essential for nicotinamide exchange, is in position to stabilize the oxocarbenium intermediate that has been proposed to proceed the hydrolysis of nicotinamide. A comparison of this structure with the ADP-ribose ternary complex and a previously reported ternary complex with the 2'-O-acetyl-ADP-ribose reaction product reveals that the ribose ring of the cofactor and the highly conserved beta1-alpha2 loop of the protein undergo significant structural rearrangements to facilitate the ordered NAD(+) reactions of nicotinamide cleavage and ADP-ribose transfer to acetate. Together, these studies provide insights into the chemistry of NAD(+) cleavage and acetylation by Sir2 proteins and have implications for the design of Sir2-specific regulatory molecules.
Structural basis for nicotinamide cleavage and ADP-ribose transfer by NAD(+)-dependent Sir2 histone/protein deacetylases.,Zhao K, Harshaw R, Chai X, Marmorstein R Proc Natl Acad Sci U S A. 2004 Jun 8;101(23):8563-8. Epub 2004 May 18. PMID:15150415[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Landry J, Sutton A, Tafrov ST, Heller RC, Stebbins J, Pillus L, Sternglanz R. The silencing protein SIR2 and its homologs are NAD-dependent protein deacetylases. Proc Natl Acad Sci U S A. 2000 May 23;97(11):5807-11. PMID:10811920 doi:http://dx.doi.org/10.1073/pnas.110148297
- ↑ Tanner KG, Landry J, Sternglanz R, Denu JM. Silent information regulator 2 family of NAD- dependent histone/protein deacetylases generates a unique product, 1-O-acetyl-ADP-ribose. Proc Natl Acad Sci U S A. 2000 Dec 19;97(26):14178-82. PMID:11106374 doi:http://dx.doi.org/10.1073/pnas.250422697
- ↑ Perrod S, Cockell MM, Laroche T, Renauld H, Ducrest AL, Bonnard C, Gasser SM. A cytosolic NAD-dependent deacetylase, Hst2p, can modulate nucleolar and telomeric silencing in yeast. EMBO J. 2001 Jan 15;20(1-2):197-209. PMID:11226170 doi:http://dx.doi.org/10.1093/emboj/20.1.197
- ↑ Borra MT, Langer MR, Slama JT, Denu JM. Substrate specificity and kinetic mechanism of the Sir2 family of NAD+-dependent histone/protein deacetylases. Biochemistry. 2004 Aug 3;43(30):9877-87. PMID:15274642 doi:http://dx.doi.org/10.1021/bi049592e
- ↑ Wilson JM, Le VQ, Zimmerman C, Marmorstein R, Pillus L. Nuclear export modulates the cytoplasmic Sir2 homologue Hst2. EMBO Rep. 2006 Dec;7(12):1247-51. Epub 2006 Nov 17. PMID:17110954 doi:http://dx.doi.org/10.1038/sj.embor.7400829
- ↑ Zhao K, Harshaw R, Chai X, Marmorstein R. Structural basis for nicotinamide cleavage and ADP-ribose transfer by NAD(+)-dependent Sir2 histone/protein deacetylases. Proc Natl Acad Sci U S A. 2004 Jun 8;101(23):8563-8. Epub 2004 May 18. PMID:15150415 doi:10.1073/pnas.0401057101
|
