1tne
From Proteopedia
(New page: 200px<br /><applet load="1tne" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tne" /> '''NMR STUDY OF Z-DNA AT PHYSIOLOGICAL SALT CON...) |
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| - | [[Image:1tne.jpg|left|200px]]<br /><applet load="1tne" size=" | + | [[Image:1tne.jpg|left|200px]]<br /><applet load="1tne" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1tne" /> | caption="1tne" /> | ||
'''NMR STUDY OF Z-DNA AT PHYSIOLOGICAL SALT CONDITIONS, MINIMIZED AVERAGE STRUCTURE'''<br /> | '''NMR STUDY OF Z-DNA AT PHYSIOLOGICAL SALT CONDITIONS, MINIMIZED AVERAGE STRUCTURE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Various oligonucleotides containing 8-methylguanine (m8G) have been | + | Various oligonucleotides containing 8-methylguanine (m8G) have been synthesized and their structures and thermodynamic properties investigated. Introduction Of M8G into DNA sequences markedly stabilizes the Z conformation under low salt conditions. The hexamer d(CGC[M8G]CG)2 exhibits a CD spectrum characteristic of the Z conformation under physiological salt conditions. The NOE-restrained refinement unequivocally demonstrated that d(CGC[m8G]CG)2 adopts a Z structure with all guanines in the syn conformation. The refined NMR structure is very similar to the Z form crystal structure of d(CGCGCG)2, with a root mean square deviation of 0.6 between the two structures. The contribution of m8G to the stabilization of Z-DNA has been estimated from the mid-point NaCl concentrations for the B-Z transition of various m8G-containing oligomers. The presence of m8G in d(CGC[m8G]CG)2 stabilizes the Z conformation by at least deltaG = -0.8 kcal/mol relative to the unmodified hexamer. The Z conformation was further stabilized by increasing the number of m8Gs incorporated and destabilized by incorporating syn-A or syn-T, found respectively in the (A,T)-containing alternating and non-alternating pyrimidine-purine sequences. The results suggest that the chemically less reactive m8G base is a useful agent for studying molecular interactions of Z-DNA or other DNA structures that incorporate syn-G conformation. |
==About this Structure== | ==About this Structure== | ||
| - | 1TNE 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:// | + | 1TNE 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=1TNE OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Saito, I.]] | [[Category: Saito, I.]] | ||
[[Category: Sugiyama, H.]] | [[Category: Sugiyama, H.]] | ||
| - | [[Category: Wang, A | + | [[Category: Wang, A H.J.]] |
[[Category: z-dna]] | [[Category: z-dna]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:15:23 2008'' |
Revision as of 13:15, 21 February 2008
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NMR STUDY OF Z-DNA AT PHYSIOLOGICAL SALT CONDITIONS, MINIMIZED AVERAGE STRUCTURE
Overview
Various oligonucleotides containing 8-methylguanine (m8G) have been synthesized and their structures and thermodynamic properties investigated. Introduction Of M8G into DNA sequences markedly stabilizes the Z conformation under low salt conditions. The hexamer d(CGC[M8G]CG)2 exhibits a CD spectrum characteristic of the Z conformation under physiological salt conditions. The NOE-restrained refinement unequivocally demonstrated that d(CGC[m8G]CG)2 adopts a Z structure with all guanines in the syn conformation. The refined NMR structure is very similar to the Z form crystal structure of d(CGCGCG)2, with a root mean square deviation of 0.6 between the two structures. The contribution of m8G to the stabilization of Z-DNA has been estimated from the mid-point NaCl concentrations for the B-Z transition of various m8G-containing oligomers. The presence of m8G in d(CGC[m8G]CG)2 stabilizes the Z conformation by at least deltaG = -0.8 kcal/mol relative to the unmodified hexamer. The Z conformation was further stabilized by increasing the number of m8Gs incorporated and destabilized by incorporating syn-A or syn-T, found respectively in the (A,T)-containing alternating and non-alternating pyrimidine-purine sequences. The results suggest that the chemically less reactive m8G base is a useful agent for studying molecular interactions of Z-DNA or other DNA structures that incorporate syn-G conformation.
About this Structure
1TNE is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Synthesis, structure and thermodynamic properties of 8-methylguanine-containing oligonucleotides: Z-DNA under physiological salt conditions., Sugiyama H, Kawai K, Matsunaga A, Fujimoto K, Saito I, Robinson H, Wang AH, Nucleic Acids Res. 1996 Apr 1;24(7):1272-8. PMID:8614630
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