1s7g
From Proteopedia
Structural Basis for the Mechanism and Regulation of Sir2 Enzymes
Structural highlights
FunctionNPD2_ARCFU NAD-dependent protein deacetylase which modulates the activities of several enzymes which are inactive in their acetylated form. Deacetylates the N-terminal lysine residue of Alba, the major archaeal chromatin protein and that, in turn, increases Alba's DNA binding affinity, thereby repressing transcription (By similarity).[HAMAP-Rule:MF_01121] 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 PubMedSir2 proteins form a family of NAD(+)-dependent protein deacetylases required for diverse biological processes, including transcriptional silencing, suppression of rDNA recombination, control of p53 activity, regulation of acetyl-CoA synthetase, and aging. Although structures of Sir2 enzymes in the presence and absence of peptide substrate or NAD(+) have been determined, the role of the enzyme in the mechanism of deacetylation and NAD(+) cleavage is still unclear. Here, we present additional structures of Sir2Af2 in several differently complexed states: in a productive complex with NAD(+), in a nonproductive NAD(+) complex with bound ADP-ribose, and in the unliganded state. We observe a new mode of NAD(+) binding that seems to depend on acetyl-lysine binding, in which the nicotinamide ring of NAD(+) is buried in the highly conserved "C" pocket of the enzyme. We propose a detailed structure-based mechanism for deacetylation and nicotinamide inhibition of Sir2 consistent with mutagenesis and enzymatic studies. Structural basis for the mechanism and regulation of Sir2 enzymes.,Avalos JL, Boeke JD, Wolberger C Mol Cell. 2004 Mar 12;13(5):639-48. PMID:15023335[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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