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1tne
From Proteopedia
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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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