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| | {{STRUCTURE_1n2w| PDB=1n2w | SCENE= }} | | {{STRUCTURE_1n2w| PDB=1n2w | SCENE= }} |
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| - | '''Solution Structure of 8OG:G mismatch containing duplex'''
| + | ===Solution Structure of 8OG:G mismatch containing duplex=== |
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| - | ==Overview==
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| - | Deoxyguanosine residues are hydroxylated by reactive oxygen species at the C-8 position to form 8-hydroxy-2'-deoxyguanosine (8-OG), one of the most important mutagenic lesions in DNA. Though the spontaneous G:C to C:G transversions are rare events, the pathways leading to this mutation are not established. An 8-OG:G mispair, if not corrected by DNA repair enzymes, could lead to G:C to C:G transversions. NMR spectroscopy and restrained molecular dynamics calculations are used to refine the solution structure of the base mismatch formed by the 8-OG:G pair on a self complementary DNA dodecamer duplex d(CGCGAATT(8-O)GGCG)(2). The results reveal that the 8-OG base is inserted into the helix and forms Hoogsteen base-pairing with the G on the opposite strand. The 8-OG:G base-pairs are seen to be stabilized by two hydrogen bonding interactions, one between the H7 of the 8-OG and the O6 of the G, and a three-center hydrogen bonding between the O8 of the 8-OG and the imino and amino protons of the G. The 8-OG:G base-pairs are very well stacked between the Watson-Crick base-paired flanking bases. Both strands of the DNA duplex adopt right-handed conformations. All of the unmodified bases, including the G at the lesion site, adopt anti glycosidic torsion angles and form Watson-Crick base-pairs. At the lesion site, the 8-OG residues adopt syn conformations. The structural studies demonstrate that 8-OG(syn):G(anti) forms a stable pair in the interior of the duplex, providing a basis for the in vivo incorporation of G opposite 8-OG. Calculated helical parameters and backbone torsional angles, and the observed 31P chemical shifts, indicate that the structure of the duplex is perturbed near lesion sites, with the local unwinding of the double helix. The melting temperature of the 8-OG:G containing duplex is only 2.6 deg. C less than the t(m) of the unmodified duplex.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_12498794}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 12498794 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_12498794}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N2W OCA]. | + | Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N2W OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: G:g mismatch]] | | [[Category: G:g mismatch]] |
| | [[Category: Oxidative damage]] | | [[Category: Oxidative damage]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 02:01:18 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 21:41:34 2008'' |
Revision as of 18:41, 27 July 2008
Template:STRUCTURE 1n2w
Solution Structure of 8OG:G mismatch containing duplex
Template:ABSTRACT PUBMED 12498794
About this Structure
Full experimental information is available from OCA.
Reference
Solution structure of a DNA duplex containing 8-hydroxy-2'-deoxyguanosine opposite deoxyguanosine., Thiviyanathan V, Somasunderam A, Hazra TK, Mitra S, Gorenstein DG, J Mol Biol. 2003 Jan 17;325(3):433-42. PMID:12498794
Page seeded by OCA on Sun Jul 27 21:41:34 2008
