5ff8: Difference between revisions
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==TDG enzyme-product complex== | |||
<StructureSection load='5ff8' size='340' side='right' caption='[[5ff8]], [[Resolution|resolution]] 1.70Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[5ff8]] is a 3 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5FF8 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5FF8 FirstGlance]. <br> | |||
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=AAB:2-DEOXY-RIBOFURANOSE-5-MONOPHOSPHATE'>AAB</scene></td></tr> | |||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Thymine-DNA_glycosylase Thymine-DNA glycosylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.2.29 3.2.2.29] </span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ff8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ff8 OCA], [http://pdbe.org/5ff8 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5ff8 RCSB], [http://www.ebi.ac.uk/pdbsum/5ff8 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5ff8 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[[http://www.uniprot.org/uniprot/TDG_HUMAN TDG_HUMAN]] In the DNA of higher eukaryotes, hydrolytic deamination of 5-methylcytosine to thymine leads to the formation of G/T mismatches. This enzyme corrects G/T mispairs to G/C pairs. It is capable of hydrolyzing the carbon-nitrogen bond between the sugar-phosphate backbone of the DNA and a mispaired thymine. In addition to the G/T, it can remove thymine also from C/T and T/T mispairs in the order G/T >> C/T > T/T. It has no detectable activity on apyrimidinic sites and does not catalyze the removal of thymine from A/T pairs or from single-stranded DNA. It can also remove uracil and 5-bromouracil from mispairs with guanine. | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Thymine DNA Glycosylase (TDG) is a base excision repair enzyme functioning in DNA repair and epigenetic regulation. TDG removes thymine from mutagenic G.T mispairs arising from deamination of 5-methylcytosine (mC), and it processes other deamination-derived lesions including uracil (U). Essential for DNA demethylation, TDG excises 5-formylcytosine and 5-carboxylcytosine, derivatives of mC generated by Tet (ten-eleven translocation) enzymes. Here, we report structural and functional studies of TDG82-308, a new construct containing 29 more N-terminal residues than TDG111-308, the construct used for previous structures of DNA-bound TDG. Crystal structures and NMR experiments demonstrate that most of these N-terminal residues are disordered, for substrate- or product-bound TDG82-308 Nevertheless, G.T substrate affinity and glycosylase activity of TDG82-308 greatly exceeds that of TDG111-308 and is equivalent to full-length TDG. We report the first high-resolution structures of TDG in an enzyme-substrate complex, for G.U bound to TDG82-308 (1.54 A) and TDG111-308 (1.71 A), revealing new enzyme-substrate contacts, direct and water-mediated. We also report a structure of the TDG82-308 product complex (1.70 A). TDG82-308 forms unique enzyme-DNA interactions, supporting its value for structure-function studies. The results advance understanding of how TDG recognizes and removes modified bases from DNA, particularly those resulting from deamination. | |||
Structural basis of damage recognition by thymine DNA glycosylase: Key roles for N-terminal residues.,Coey CT, Malik SS, Pidugu LS, Varney KM, Pozharski E, Drohat AC Nucleic Acids Res. 2016 Aug 31. pii: gkw768. PMID:27580719<ref>PMID:27580719</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
[[Category: Malik, S | <div class="pdbe-citations 5ff8" style="background-color:#fffaf0;"></div> | ||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Thymine-DNA glycosylase]] | |||
[[Category: Drohat, A C]] | |||
[[Category: Malik, S S]] | |||
[[Category: Pozharski, E]] | [[Category: Pozharski, E]] | ||
[[Category: | [[Category: G-t mismatch-specific thymine dna glycosylase-dna complex]] | ||
[[Category: Hydrolase-dna complex]] | |||