2h2g

The Structural Basis of Sirtuin substrate affinity

spinqualitylabelsall models 2h2g, resolution 1.63Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2h2g is a 2 chain structure with sequence from Atcc 43589. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ZN NonStd Res: ALY Gene: npdA (ATCC 43589) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [NPD_THEMA] NAD-dependent protein deacetylase which modulates the activities of several enzymes which are inactive in their acetylated form. Has also depropionylation activity in vitro. Also able to ADP-ribosylate peptide substrates with Arg or Lys in the +2 position. The role of this function in vivo is not clear. 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 Sirtuins comprise a family of enzymes that catalyze the deacetylation of acetyllysine side chains in a reaction that consumes NAD+. Although several crystal structures of sirtuins bound to non-native acetyl peptides have been determined, relatively little about how sirtuins discriminate among different substrates is understood. We have carried out a systematic structural and thermodynamic analysis of several peptides bound to a single sirtuin, the Sir2 homologue from Thermatoga maritima (Sir2Tm). We report structures of five different forms of Sir2Tm: two forms bound to the p53 C-terminal tail in the acetylated and unacetylated states, two forms bound to putative acetyl peptide substrates derived from the structured domains of histones H3 and H4, and one form bound to polypropylene glycol (PPG), which resembles the apoenzyme. The structures reveal previously unobserved complementary side chain interactions between Sir2Tm and the first residue N-terminal to the acetyllysine (position -1) and the second residue C-terminal to the acetyllysine (position +2). Isothermal titration calorimetry was used to compare binding constants between wild-type and mutant forms of Sir2Tm and between additional acetyl peptide substrates with substitutions at positions -1 and +2. The results are consistent with a model in which peptide positions -1 and +2 play a significant role in sirtuin substrate binding. This model provides a framework for identifying sirtuin substrates. The structural basis of sirtuin substrate affinity.,Cosgrove MS, Bever K, Avalos JL, Muhammad S, Zhang X, Wolberger C Biochemistry. 2006 Jun 20;45(24):7511-21. PMID:16768447 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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