1mwj
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(New page: 200px<br /><applet load="1mwj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mwj, resolution 2.85Å" /> '''Crystal Structure of...)
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Revision as of 19:38, 20 November 2007
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Crystal Structure of a MUG-DNA pseudo substrate complex
Overview
The bacterial mismatch-specific uracil-DNA glycosylase (MUG) and, eukaryotic thymine-DNA glycosylase (TDG) enzymes form a homologous family, of DNA glycosylases that initiate base-excision repair of G:U/T, mismatches. Despite low sequence homology, the MUG/TDG enzymes are, structurally related to the uracil-DNA glycosylase enzymes, but have a, very different mechanism for substrate recognition. We have now determined, the crystal structure of the Escherichia coli MUG enzyme complexed with an, oligonucleotide containing a non-hydrolysable deoxyuridine analogue, mismatched with guanine, providing the first structure of an intact, substrate-nucleotide productively bound to a hydrolytic DNA glycosylase., The structure of this complex explains the preference for G:U over G:T, mispairs, and reveals an essentially non-specific pyrimidine-binding, pocket that allows MUG/TDG enzymes to excise the alkylated base, 3, N(4)-ethenocytosine. Together with structures for the free enzyme and for, an abasic-DNA product complex, the MUG-substrate analogue complex reveals, the conformational changes accompanying the catalytic cycle of substrate, binding, base excision and product release.
About this Structure
1MWJ is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structure of a thwarted mismatch glycosylase DNA repair complex., Barrett TE, Scharer OD, Savva R, Brown T, Jiricny J, Verdine GL, Pearl LH, EMBO J. 1999 Dec 1;18(23):6599-609. PMID:10581234
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