1XAM

Cobalt hexammine induced tautameric shift in Z-DNA: structure of d(CGCGCA).d(TGCGCG) in two crystal forms.

1XAM の概要

• エントリーDOI: 10.2210/pdb1xam/pdb
• 関連するPDBエントリー: 1XA2
• 分子名称: CGCGCA, TGCGCG, TG, ... (5 entities in total)
• 機能のキーワード: double helix, z-dna, dna
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 4957.42

構造登録者

Thiyagarajan, S.,Rajan, S.S.,Gautham, N. (登録日: 2004-08-26, 公開日: 2004-11-16, 最終更新日: 2024-04-03)

主引用文献

Thiyagarajan, S.,Rajan, S.S.,Gautham, N.
Cobalt hexammine induced tautomeric shift in Z-DNA: the structure of d(CGCGCA)*d(TGCGCG) in two crystal forms.
Nucleic Acids Res., 32:5945-5953, 2004

PubMed Abstract: We report here the crystal structure of the DNA hexamer duplex d(CGCGCA)*d(TGCGCG) at 1.71 A resolution. The crystals, in orthorhombic space group, were grown in the presence of cobalt hexammine, a known inducer of the left-handed Z form of DNA. The interaction of this ion with the DNA helix results in a change of the adenine base from the common amino tautomeric form to the imino tautomer. Consequently the A:T base pair is disrupted from the normal Watson-Crick base pairing to a 'wobble' like base pairing. This change is accommodated easily within the helix, and the helical parameters are those expected for Z-DNA. When the cobalt hexammine concentration is decreased slightly in the crystallization conditions, the duplex crystallizes in a different, hexagonal space group, with two hexamer duplexes in the asymmetric unit. One of these is situated on a crystallographic 6-fold screw axis, leading to disorder. The tautomeric shift is not observed in this space group. We show that the change in inter-helix interactions that lead to the two different space groups probably arise from the small decrease in ion concentration, and consequently disordered positions for the ion.

PubMed: 15534365
DOI: 10.1093/nar/gkh919

実験手法

X-RAY DIFFRACTION (1.86 Å)