3i2o

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Revision as of 07:55, 1 November 2017

Crystal Structure of AlkB in complex with Fe(II), 2-oxoglutarate and methylated trinucleotide T-meA-T

Structural highlights

3i2o is a 2 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:	,
NonStd Res:
Related:	2fd8, 2iuw, 3buc, 3i3m, 3i3q, 3i49
Gene:	aidD, alkB, b2212, JW2200 (ECOLI)
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[ALKB_ECOLI] Dioxygenase that repairs alkylated DNA and RNA containing 3-methylcytosine or 1-methyladenine by oxidative demethylation. Has highest activity towards 3-methylcytosine. Has lower activity towards alkylated DNA containing ethenoadenine, and no detectable activity towards 1-methylguanine or 3-methylthymine. Accepts double-stranded and single-stranded substrates. Requires molecular oxygen, alpha-ketoglutarate and iron. Provides extensive resistance to alkylating agents such as MMS and DMS (SN2 agents), but not to MMNG and MNU (SN1 agents).^[1] ^[2] ^[3] ^[4] ^[5] ^[6]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Promiscuous substrate recognition, the ability to catalyze transformations of chemically diverse compounds, is an evolutionarily advantageous, but poorly understood phenomenon. The promiscuity of DNA repair enzymes is particularly important, because it enables diverse kinds of damage to different nucleotide bases to be repaired in a metabolically parsimonious manner. We present enzymological and crystallographic studies of the mechanisms underlying promiscuous substrate recognition by Escherichia coli AlkB, a DNA repair enzyme that removes methyl adducts and some larger alkylation lesions from endocyclic positions on purine and pyrimidine bases. In vitro Michaelis-Menten analyses on a series of alkylated bases show high activity in repairing N1-methyladenine (m1A) and N3-methylcytosine (m3C), comparatively low activity in repairing 1,N(6)-ethenoadenine, and no detectable activity in repairing N1-methylguanine or N3-methylthymine. AlkB has a substantially higher k(cat) and K(m) for m3C compared with m1A. Therefore, the enzyme maintains similar net activity on the chemically distinct substrates by increasing the turnover rate of the substrate with nominally lower affinity. Cocrystal structures provide insight into the structural basis of this "k(cat)/K(m) compensation," which makes a significant contribution to promiscuous substrate recognition by AlkB. In analyzing a large ensemble of crystal structures solved in the course of these studies, we observed 2 discrete global conformations of AlkB differing in the accessibility of a tunnel hypothesized to control diffusion of the O(2) substrate into the active site. Steric interactions between a series of protein loops control this conformational transition and present a plausible mechanism for preventing O(2) binding before nucleotide substrate binding.

Enzymological and structural studies of the mechanism of promiscuous substrate recognition by the oxidative DNA repair enzyme AlkB.,Yu B, Hunt JF Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14315-20. Epub 2009 Aug 11. PMID:19706517^[7]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Falnes PO, Johansen RF, Seeberg E. AlkB-mediated oxidative demethylation reverses DNA damage in Escherichia coli. Nature. 2002 Sep 12;419(6903):178-82. PMID:12226668 doi:10.1038/nature01048
↑ Aas PA, Otterlei M, Falnes PO, Vagbo CB, Skorpen F, Akbari M, Sundheim O, Bjoras M, Slupphaug G, Seeberg E, Krokan HE. Human and bacterial oxidative demethylases repair alkylation damage in both RNA and DNA. Nature. 2003 Feb 20;421(6925):859-63. PMID:12594517 doi:10.1038/nature01363
↑ Yu B, Edstrom WC, Benach J, Hamuro Y, Weber PC, Gibney BR, Hunt JF. Crystal structures of catalytic complexes of the oxidative DNA/RNA repair enzyme AlkB. Nature. 2006 Feb 16;439(7078):879-84. PMID:16482161 doi:10.1038/nature04561
↑ Yu B, Hunt JF. Enzymological and structural studies of the mechanism of promiscuous substrate recognition by the oxidative DNA repair enzyme AlkB. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14315-20. Epub 2009 Aug 11. PMID:19706517
↑ Yi C, Jia G, Hou G, Dai Q, Zhang W, Zheng G, Jian X, Yang CG, Cui Q, He C. Iron-catalysed oxidation intermediates captured in a DNA repair dioxygenase. Nature. 2010 Nov 11;468(7321):330-3. PMID:21068844 doi:10.1038/nature09497
↑ Holland PJ, Hollis T. Structural and mutational analysis of Escherichia coli AlkB provides insight into substrate specificity and DNA damage searching. PLoS One. 2010 Jan 13;5(1):e8680. PMID:20084272 doi:10.1371/journal.pone.0008680
↑ Yu B, Hunt JF. Enzymological and structural studies of the mechanism of promiscuous substrate recognition by the oxidative DNA repair enzyme AlkB. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14315-20. Epub 2009 Aug 11. PMID:19706517

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/3i2o"

@@ Line 1: / Line 1: @@
 ==Crystal Structure of AlkB in complex with Fe(II), 2-oxoglutarate and methylated trinucleotide T-meA-T==
 <StructureSection load='3i2o' size='340' side='right' caption='[[3i2o]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
@@ Line 7: / Line 8: @@
 <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[2fd8|2fd8]], [[2iuw|2iuw]], [[3buc|3buc]], [[3i3m|3i3m]], [[3i3q|3i3q]], [[3i49|3i49]]</td></tr>
 <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">aidD, alkB, b2212, JW2200 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=83333 ECOLI])</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=3i2o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3i2o OCA], [http://pdbe.org/3i2o PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3i2o RCSB], [http://www.ebi.ac.uk/pdbsum/3i2o PDBsum]</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=3i2o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3i2o OCA], [http://pdbe.org/3i2o PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3i2o RCSB], [http://www.ebi.ac.uk/pdbsum/3i2o PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3i2o ProSAT]</span></td></tr>
 </table>
 == Function ==
@@ Line 30: / Line 31: @@
 </div>
 <div class="pdbe-citations 3i2o" style="background-color:#fffaf0;"></div>
-==See Also==
-*[[Dioxygenase|Dioxygenase]]
 == References ==
 <references/>

3i2o

From Proteopedia

Revision as of 07:55, 1 November 2017

Crystal Structure of AlkB in complex with Fe(II), 2-oxoglutarate and methylated trinucleotide T-meA-T

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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