1jvc
From Proteopedia
(New page: 200px<br /><applet load="1jvc" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jvc" /> '''Dimeric DNA Quadruplex Containing Major Groo...) |
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| - | [[Image:1jvc.gif|left|200px]]<br /><applet load="1jvc" size=" | + | [[Image:1jvc.gif|left|200px]]<br /><applet load="1jvc" size="350" color="white" frame="true" align="right" spinBox="true" |
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'''Dimeric DNA Quadruplex Containing Major Groove-Aligned A.T.A.T and G.C.G.C Tetrads Stabilized by Inter-Subunit Watson-Crick A:T and G:C Pairs'''<br /> | '''Dimeric DNA Quadruplex Containing Major Groove-Aligned A.T.A.T and G.C.G.C Tetrads Stabilized by Inter-Subunit Watson-Crick A:T and G:C Pairs'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We report on an NMR study of unlabeled and uniformly 13C,15N-labeled | + | We report on an NMR study of unlabeled and uniformly 13C,15N-labeled d(GAGCAGGT) sequence in 1 M NaCl solution, conditions under which it forms a head-to-head dimeric quadruplex containing sequentially stacked G-C-G-C, G-G-G-G and A-T-A-T tetrads. We have identified, for the first time, a slipped A-T-A-T tetrad alignment, involving recognition of Watson-Crick A-T pairs along the major groove edges of opposing adenine residues. Strikingly, both Watson-Crick G-C and A-T pairings within the direct G-C-G-C and slipped A-T-A-T tetrads, respectively, occur between rather than within hairpin subunits of the dimeric d(GAGCAGGT) quadruplex. The hairpin turns in the head-to-head dimeric quadruplex involve single adenine residues and adds to our knowledge of chain reversal involving edgewise loops in DNA quadruplexes. Our structural studies, together with those from other laboratories, definitively establish that DNA quadruplex formation is not restricted to G(n) repeat sequences, with their characteristic stacked uniform G-G-G-G tetrad architectures. Rather, the quadruplex fold is a more versatile and robust architecture, accessible to a range of mixed sequences, with the potential to facilitate G-C-G-C and A-T-A-T tetrad through major and minor groove alignment, in addition to G-G-G-G tetrad formation. The definitive experimental identification of such major groove-aligned mixed A-T-A-T and G-C-G-C tetrads within a quadruplex scaffold, has important implications for the potential alignment of duplex segments during homologous recombination. |
==About this Structure== | ==About this Structure== | ||
| - | 1JVC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | + | 1JVC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JVC OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Kettani, A.]] | [[Category: Kettani, A.]] | ||
[[Category: Majumdar, A.]] | [[Category: Majumdar, A.]] | ||
| - | [[Category: Patel, D | + | [[Category: Patel, D J.]] |
[[Category: Skripkin, E.]] | [[Category: Skripkin, E.]] | ||
[[Category: Zhang, N.]] | [[Category: Zhang, N.]] | ||
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[[Category: inter-subunit watson-crick pairs]] | [[Category: inter-subunit watson-crick pairs]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:27:08 2008'' |
Revision as of 11:27, 21 February 2008
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Dimeric DNA Quadruplex Containing Major Groove-Aligned A.T.A.T and G.C.G.C Tetrads Stabilized by Inter-Subunit Watson-Crick A:T and G:C Pairs
Overview
We report on an NMR study of unlabeled and uniformly 13C,15N-labeled d(GAGCAGGT) sequence in 1 M NaCl solution, conditions under which it forms a head-to-head dimeric quadruplex containing sequentially stacked G-C-G-C, G-G-G-G and A-T-A-T tetrads. We have identified, for the first time, a slipped A-T-A-T tetrad alignment, involving recognition of Watson-Crick A-T pairs along the major groove edges of opposing adenine residues. Strikingly, both Watson-Crick G-C and A-T pairings within the direct G-C-G-C and slipped A-T-A-T tetrads, respectively, occur between rather than within hairpin subunits of the dimeric d(GAGCAGGT) quadruplex. The hairpin turns in the head-to-head dimeric quadruplex involve single adenine residues and adds to our knowledge of chain reversal involving edgewise loops in DNA quadruplexes. Our structural studies, together with those from other laboratories, definitively establish that DNA quadruplex formation is not restricted to G(n) repeat sequences, with their characteristic stacked uniform G-G-G-G tetrad architectures. Rather, the quadruplex fold is a more versatile and robust architecture, accessible to a range of mixed sequences, with the potential to facilitate G-C-G-C and A-T-A-T tetrad through major and minor groove alignment, in addition to G-G-G-G tetrad formation. The definitive experimental identification of such major groove-aligned mixed A-T-A-T and G-C-G-C tetrads within a quadruplex scaffold, has important implications for the potential alignment of duplex segments during homologous recombination.
About this Structure
1JVC is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Dimeric DNA quadruplex containing major groove-aligned A-T-A-T and G-C-G-C tetrads stabilized by inter-subunit Watson-Crick A-T and G-C pairs., Zhang N, Gorin A, Majumdar A, Kettani A, Chernichenko N, Skripkin E, Patel DJ, J Mol Biol. 2001 Oct 5;312(5):1073-88. PMID:11580251
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