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[[ | ==Structure of an unusual 3-METHYLADENINE DNA GLYCOSYLASE II (ALKA) FROM DEINOCOCCUS RADIODURANS== | ||
<StructureSection load='2yg8' size='340' side='right' caption='[[2yg8]], [[Resolution|resolution]] 2.00Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2yg8]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2YG8 OCA]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene></td></tr> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2yg9|2yg9]]</td></tr> | |||
<tr><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glucokinase Glucokinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.1.2 2.7.1.2] </span></td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2yg8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2yg8 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2yg8 RCSB], [http://www.ebi.ac.uk/pdbsum/2yg8 PDBsum]</span></td></tr> | |||
<table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
3-Methyladenine DNA glycosylase II (AlkA) is a DNA-repair enzyme that removes alkylated bases in DNA via the base-excision repair (BER) pathway. The enzyme belongs to the helix-hairpin-helix (HhH) superfamily of DNA glycosylases and possesses broad substrate specificity. In the genome of Deinococcus radiodurans, two genes encoding putative AlkA have been identified (Dr_2074 and Dr_2584). Dr_2074 is a homologue of human AlkA (MPG or AAG) and Dr_2584 is a homologue of bacterial AlkAs. Here, the three-dimensional structure of Dr_2584 (DrAlkA2) is presented and compared with the previously determined structure of Escherichia coli AlkA (EcAlkA). The results show that the enzyme consists of two helical-bundle domains separated by a wide DNA-binding cleft and contains an HhH motif. Overall, the protein fold is similar to the two helical-bundle domains of EcAlkA, while the third N-terminal mixed alpha/beta domain observed in EcAlkA is absent. Substrate-specificity analyses show that DrAlkA2, like EcAlkA, is able to remove both 3-methyladenine (3meA) and 7-methylguanine (7meG) from DNA; however, the enzyme possesses no activity towards 1,N(6)-ethenoadenine (A) and hypoxanthine (Hx). In addition, it shows activity towards the AlkB dioxygenase substrates 3-methylcytosine (3meC) and 1-methyladenine (1meA). Thus, the enzyme seems to preferentially repair methylated bases with weakened N-glycosidic bonds; this is an unusual specificity for a bacterial AlkA protein and is probably dictated by a combination of the wide DNA-binding cleft and a highly accessible specificity pocket. | |||
Structure-function studies of an unusual 3-methyladenine DNA glycosylase II (AlkA) from Deinococcus radiodurans.,Moe E, Hall DR, Leiros I, Monsen VT, Timmins J, McSweeney S Acta Crystallogr D Biol Crystallogr. 2012 Jun;68(Pt 6):703-12. Epub 2012 May 17. PMID:22683793<ref>PMID:22683793</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Hall, D R.]] | [[Category: Hall, D R.]] | ||
[[Category: Leiros, I.]] | [[Category: Leiros, I.]] | ||
Revision as of 10:52, 14 May 2014
Structure of an unusual 3-METHYLADENINE DNA GLYCOSYLASE II (ALKA) FROM DEINOCOCCUS RADIODURANSStructure of an unusual 3-METHYLADENINE DNA GLYCOSYLASE II (ALKA) FROM DEINOCOCCUS RADIODURANS
Structural highlights
Publication Abstract from PubMed3-Methyladenine DNA glycosylase II (AlkA) is a DNA-repair enzyme that removes alkylated bases in DNA via the base-excision repair (BER) pathway. The enzyme belongs to the helix-hairpin-helix (HhH) superfamily of DNA glycosylases and possesses broad substrate specificity. In the genome of Deinococcus radiodurans, two genes encoding putative AlkA have been identified (Dr_2074 and Dr_2584). Dr_2074 is a homologue of human AlkA (MPG or AAG) and Dr_2584 is a homologue of bacterial AlkAs. Here, the three-dimensional structure of Dr_2584 (DrAlkA2) is presented and compared with the previously determined structure of Escherichia coli AlkA (EcAlkA). The results show that the enzyme consists of two helical-bundle domains separated by a wide DNA-binding cleft and contains an HhH motif. Overall, the protein fold is similar to the two helical-bundle domains of EcAlkA, while the third N-terminal mixed alpha/beta domain observed in EcAlkA is absent. Substrate-specificity analyses show that DrAlkA2, like EcAlkA, is able to remove both 3-methyladenine (3meA) and 7-methylguanine (7meG) from DNA; however, the enzyme possesses no activity towards 1,N(6)-ethenoadenine (A) and hypoxanthine (Hx). In addition, it shows activity towards the AlkB dioxygenase substrates 3-methylcytosine (3meC) and 1-methyladenine (1meA). Thus, the enzyme seems to preferentially repair methylated bases with weakened N-glycosidic bonds; this is an unusual specificity for a bacterial AlkA protein and is probably dictated by a combination of the wide DNA-binding cleft and a highly accessible specificity pocket. Structure-function studies of an unusual 3-methyladenine DNA glycosylase II (AlkA) from Deinococcus radiodurans.,Moe E, Hall DR, Leiros I, Monsen VT, Timmins J, McSweeney S Acta Crystallogr D Biol Crystallogr. 2012 Jun;68(Pt 6):703-12. Epub 2012 May 17. PMID:22683793[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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