|
|
| Line 4: |
Line 4: |
| | == Structural highlights == | | == Structural highlights == |
| | <table><tr><td colspan='2'>[[4ea4]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EA4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4EA4 FirstGlance]. <br> | | <table><tr><td colspan='2'>[[4ea4]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EA4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4EA4 FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=5HU:5-HYDROXYMETHYLURIDINE-2-DEOXY-5-MONOPHOSPHATE'>5HU</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2Å</td></tr> |
| | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=5HU:5-HYDROXYMETHYLURIDINE-2-DEOXY-5-MONOPHOSPHATE'>5HU</scene></td></tr> |
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4ea4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ea4 OCA], [https://pdbe.org/4ea4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ea4 RCSB], [https://www.ebi.ac.uk/pdbsum/4ea4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ea4 ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4ea4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ea4 OCA], [https://pdbe.org/4ea4 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ea4 RCSB], [https://www.ebi.ac.uk/pdbsum/4ea4 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ea4 ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[https://www.uniprot.org/uniprot/MBD4_HUMAN MBD4_HUMAN]] Mismatch-specific DNA N-glycosylase involved in DNA repair. Has thymine glycosylase activity and is specific for G:T mismatches within methylated and unmethylated CpG sites. Can also remove uracil or 5-fluorouracil in G:U mismatches. Has no lyase activity. Was first identified as methyl-CpG-binding protein.<ref>PMID:10097147</ref> <ref>PMID:10930409</ref>
| + | [https://www.uniprot.org/uniprot/MBD4_HUMAN MBD4_HUMAN] Mismatch-specific DNA N-glycosylase involved in DNA repair. Has thymine glycosylase activity and is specific for G:T mismatches within methylated and unmethylated CpG sites. Can also remove uracil or 5-fluorouracil in G:U mismatches. Has no lyase activity. Was first identified as methyl-CpG-binding protein.<ref>PMID:10097147</ref> <ref>PMID:10930409</ref> |
| - | <div style="background-color:#fffaf0;">
| + | |
| - | == Publication Abstract from PubMed ==
| + | |
| - | Active DNA demethylation in mammals occurs via hydroxylation of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC) by the ten-eleven translocation family of proteins (TETs). 5hmC residues in DNA can be further oxidized by TETs to 5-carboxylcytosines and/or deaminated by the Activation Induced Deaminase/Apolipoprotein B mRNA-editing enzyme complex family proteins to 5-hydromethyluracil (5hmU). Excision and replacement of these intermediates is initiated by DNA glycosylases such as thymine-DNA glycosylase (TDG), methyl-binding domain protein 4 (MBD4) and single-strand specific monofunctional uracil-DNA glycosylase 1 in the base excision repair pathway. Here, we report detailed biochemical and structural characterization of human MBD4 which contains mismatch-specific TDG activity. Full-length as well as catalytic domain (residues 426-580) of human MBD4 (MBD4(cat)) can remove 5hmU when opposite to G with good efficiency. Here, we also report six crystal structures of human MBD4(cat): an unliganded form and five binary complexes with duplex DNA containing a T*G, 5hmU*G or AP*G (apurinic/apyrimidinic) mismatch at the target base pair. These structures reveal that MBD4(cat) uses a base flipping mechanism to specifically recognize thymine and 5hmU. The recognition mechanism of flipped-out 5hmU bases in MBD4(cat) active site supports the potential role of MBD4, together with TDG, in maintenance of genome stability and active DNA demethylation in mammals.
| + | |
| - | | + | |
| - | Biochemical and structural characterization of the glycosylase domain of MBD4 bound to thymine and 5-hydroxymethyuracil-containing DNA.,Morera S, Grin I, Vigouroux A, Couve S, Henriot V, Saparbaev M, Ishchenko AA Nucleic Acids Res. 2012 Jul 30. PMID:22848106<ref>PMID:22848106</ref>
| + | |
| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div>
| + | |
| - | <div class="pdbe-citations 4ea4" style="background-color:#fffaf0;"></div>
| + | |
| | | | |
| | ==See Also== | | ==See Also== |
| Structural highlights
Function
MBD4_HUMAN Mismatch-specific DNA N-glycosylase involved in DNA repair. Has thymine glycosylase activity and is specific for G:T mismatches within methylated and unmethylated CpG sites. Can also remove uracil or 5-fluorouracil in G:U mismatches. Has no lyase activity. Was first identified as methyl-CpG-binding protein.[1] [2]
See Also
References
- ↑ Bellacosa A, Cicchillitti L, Schepis F, Riccio A, Yeung AT, Matsumoto Y, Golemis EA, Genuardi M, Neri G. MED1, a novel human methyl-CpG-binding endonuclease, interacts with DNA mismatch repair protein MLH1. Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3969-74. PMID:10097147
- ↑ Petronzelli F, Riccio A, Markham GD, Seeholzer SH, Stoerker J, Genuardi M, Yeung AT, Matsumoto Y, Bellacosa A. Biphasic kinetics of the human DNA repair protein MED1 (MBD4), a mismatch-specific DNA N-glycosylase. J Biol Chem. 2000 Oct 20;275(42):32422-9. PMID:10930409 doi:10.1074/jbc.M004535200
|
