Structural Insights into Intermediate Steps in the Sir2 Deacetylation Reaction

William F. Hawse, Kevin G. Hoff, David G. Fatkins, Alison Daines, Olga V. Zubkova, Vern L. Schramm, Weiping Zheng, Cynthia Wolberger

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


Sirtuin enzymes comprise a unique class of NAD+-dependent protein deacetylases. Although structures of many sirtuin complexes have been determined, structural resolution of intermediate chemical steps are needed to understand the deacetylation mechanism. We report crystal structures of the bacterial sirtuin, Sir2Tm, in complex with an S-alkylamidate intermediate, analogous to the naturally occurring O-alkylamidate intermediate, and a Sir2Tm ternary complex containing a dissociated NAD+ analog and acetylated peptide. The structures and biochemical studies reveal critical roles for the invariant active site histidine in positioning the reaction intermediate, and for a conserved phenylalanine residue in shielding reaction intermediates from base exchange with nicotinamide. The new structural and biochemical studies provide key mechanistic insight into intermediate steps of the Sir2 deacetylation reaction.

Original languageEnglish (US)
Pages (from-to)1368-1377
Number of pages10
Issue number9
StatePublished - Sep 10 2008



ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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