2h4j

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spinqualitylabelsall models PDB ID 2h4j Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
, resolution 2.10Å
Ligands:	, and
Gene:	npdA (Thermotoga maritima)
Coordinates:	save as pdb, mmCIF, xml

Sir2-deacetylated peptide (from enzymatic turnover in crystal)

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

Sirtuin proteins comprise a unique class of NAD+-dependent protein deacetylases. Although several structures of sirtuins have been determined, the mechanism by which NAD+ cleavage occurs has remained unclear. We report the structures of ternary complexes containing NAD+ and acetylated peptide bound to the bacterial sirtuin Sir2Tm and to a catalytic mutant (Sir2Tm(H116Y)). NAD+ in these structures binds in a conformation different from that seen in previous structures, exposing the alpha face of the nicotinamide ribose to the carbonyl oxygen of the acetyl lysine substrate. The NAD+ conformation is identical in both structures, suggesting that proper coenzyme orientation is not dependent on contacts with the catalytic histidine. We also present the structure of Sir2Tm(H116A) bound to deacteylated peptide and 3'-O-acetyl ADP ribose. Taken together, these structures suggest a mechanism for nicotinamide cleavage in which an invariant phenylalanine plays a central role in promoting formation of the O-alkylamidate reaction intermediate and preventing nicotinamide exchange.

Disease

Known diseases associated with this structure: Adrenal cortical carcinoma OMIM:[191170], Breast cancer OMIM:[191170], Colorectal cancer OMIM:[191170], Hepatocellular carcinoma OMIM:[191170], Histiocytoma OMIM:[191170], Li-Fraumeni syndrome OMIM:[191170], Multiple malignancy syndrome OMIM:[191170], Nasopharyngeal carcinoma OMIM:[191170], Osteosarcoma OMIM:[191170], Pancreatic cancer OMIM:[191170], Thyroid carcinoma OMIM:[191170]

About this Structure

2H4J is a Protein complex structure of sequences from Thermotoga maritima. Full crystallographic information is available from OCA.

Reference

Insights into the sirtuin mechanism from ternary complexes containing NAD+ and acetylated peptide., Hoff KG, Avalos JL, Sens K, Wolberger C, Structure. 2006 Aug;14(8):1231-40. PMID:16905097

Page seeded by OCA on Thu Mar 20 17:12:31 2008