2N89

Tetrameric i-motif structure of dT-dC-dC-CFL-CFL-dC at acidic pH

2N89 の概要

• エントリーDOI: 10.2210/pdb2n89/pdb
• NMR情報: BMRB: 25840
• 分子名称: DNA (5'-D(*TP*CP*CP*(CFL)P*(CFL)P*C)-3') (1 entity in total)
• 機能のキーワード: 2'f-arac, i-motif, 2'f-ana, modified nucleotides, dna
• 由来する生物種: synthetic construct
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 6964.50

構造登録者

Abou-Assi, H.,Harkness, R.W.,Martin-Pintado, N.,Wilds, C.J.,Campos-Olivas, R.,Mittermaier, A.K.,Gonzalez, C.,Damha, M.J. (登録日: 2015-10-09, 公開日: 2016-08-17, 最終更新日: 2024-05-15)

主引用文献

Assi, H.A.,Harkness, R.W.,Martin-Pintado, N.,Wilds, C.J.,Campos-Olivas, R.,Mittermaier, A.K.,Gonzalez, C.,Damha, M.J.
Stabilization of i-motif structures by 2'-beta-fluorination of DNA.
Nucleic Acids Res., 44:4998-5009, 2016

PubMed Abstract: i-Motifs are four-stranded DNA structures consisting of two parallel DNA duplexes held together by hemi-protonated and intercalated cytosine base pairs (C:CH(+)). They have attracted considerable research interest for their potential role in gene regulation and their use as pH responsive switches and building blocks in macromolecular assemblies. At neutral and basic pH values, the cytosine bases deprotonate and the structure unfolds into single strands. To avoid this limitation and expand the range of environmental conditions supporting i-motif folding, we replaced the sugar in DNA by 2-deoxy-2-fluoroarabinose. We demonstrate that such a modification significantly stabilizes i-motif formation over a wide pH range, including pH 7. Nuclear magnetic resonance experiments reveal that 2-deoxy-2-fluoroarabinose adopts a C2'-endo conformation, instead of the C3'-endo conformation usually found in unmodified i-motifs. Nevertheless, this substitution does not alter the overall i-motif structure. This conformational change, together with the changes in charge distribution in the sugar caused by the electronegative fluorine atoms, leads to a number of favorable sequential and inter-strand electrostatic interactions. The availability of folded i-motifs at neutral pH will aid investigations into the biological function of i-motifs in vitro, and will expand i-motif applications in nanotechnology.

PubMed: 27166371
DOI: 10.1093/nar/gkw402

実験手法

SOLUTION NMR