Crystal structures of human SIRT3 displaying substrate-induced conformational changes.
Publication Type:Journal Article
Source:J Biol Chem, Volume 284, Issue 36, p.24394-405 (2009)
Keywords:Acetate-CoA Ligase, Acetylation, Humans, Mitochondria, Mitochondrial Proteins, NAD, Peptides, Protein Binding, Protein Structure, Quaternary, Sirtuin 3, Sirtuins, Structure-Activity Relationship
<p>SIRT3 is a major mitochondrial NAD(+)-dependent protein deacetylase playing important roles in regulating mitochondrial metabolism and energy production and has been linked to the beneficial effects of exercise and caloric restriction. SIRT3 is emerging as a potential therapeutic target to treat metabolic and neurological diseases. We report the first sets of crystal structures of human SIRT3, an apo-structure with no substrate, a structure with a peptide containing acetyl lysine of its natural substrate acetyl-CoA synthetase 2, a reaction intermediate structure trapped by a thioacetyl peptide, and a structure with the dethioacetylated peptide bound. These structures provide insights into the conformational changes induced by the two substrates required for the reaction, the acetylated substrate peptide and NAD(+). In addition, the binding study by isothermal titration calorimetry suggests that the acetylated peptide is the first substrate to bind to SIRT3, before NAD(+). These structures and biophysical studies provide key insight into the structural and functional relationship of the SIRT3 deacetylation activity.</p>