1wyw

From Proteopedia

Revision as of 13:03, 20 March 2008

Crystal Structure of SUMO1-conjugated thymine DNA glycosylase

Overview

Members of the small ubiquitin-like modifier (SUMO) family can be covalently attached to the lysine residue of a target protein through an enzymatic pathway similar to that used in ubiquitin conjugation, and are involved in various cellular events that do not rely on degradative signalling via the proteasome or lysosome. However, little is known about the molecular mechanisms of SUMO-modification-induced protein functional transfer. During DNA mismatch repair, SUMO conjugation of the uracil/thymine DNA glycosylase TDG promotes the release of TDG from the abasic (AP) site created after base excision, and coordinates its transfer to AP endonuclease 1, which catalyses the next step in the repair pathway. Here we report the crystal structure of the central region of human TDG conjugated to SUMO-1 at 2.1 A resolution. The structure reveals a helix protruding from the protein surface, which presumably interferes with the product DNA and thus promotes the dissociation of TDG from the DNA molecule. This helix is formed by covalent and non-covalent contacts between TDG and SUMO-1. The non-covalent contacts are also essential for release from the product DNA, as verified by mutagenesis.

Disease

Known diseases associated with this structure: Forebrain defects OMIM:[187395], Orofacial cleft 10 OMIM:[601912]

About this Structure

1WYW is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Crystal structure of thymine DNA glycosylase conjugated to SUMO-1., Baba D, Maita N, Jee JG, Uchimura Y, Saitoh H, Sugasawa K, Hanaoka F, Tochio H, Hiroaki H, Shirakawa M, Nature. 2005 Jun 16;435(7044):979-82. PMID:15959518

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