Does DNA acid fixation produce left‐handed Z structure?

FEBS Letters

Neault, J.F.¹  Tajmir-Riahi, H.A.¹  Naoui, M.¹ 

[1] Centre de recherche en photobiophysique, Université du Québev à Trois-Rivières, 3351 boulevard des Forges, CP 500, Trois-Rivières, Québec G9A 5HT, Canada

关键词: DNA;    Acid;    Denaturation;    Conformation;    FTIR spectroscopy;   

DOI  :  10.1016/0014-5793(95)00802-G

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effects of acetic acid (HCOOCH₃) on the solution structure of calf-thymus DNA are studied at pH 7.3−2.5 with acid/DNA(P) (phosphate) molar ratios (r) of , 1, 2, 10, 20 and 40. Fourier Transform infrared (FTIR) difference spectroscopy is used to establish correlations between spectral changes and base protonation, DNA conformational transition and structural variations of the acid-DNA complexes in aqueous solution. The FTIR difference spectroscopic results showed that protonation of cytosine and subsequent unpairing of the G-C base pairs begins at pH 4-3 and continues up to pH 2.5, where a complete base separation and base unstacking occur. Similarly, protonation of A-T base pairs starts at pH 4-3 and is completed at pH 2.5, where base separation and base unstacking are observed. The protonation of the G-C base pair leads to the formation of Hoogsteen-type H-bonding, before a complete G-C disruption. The biopolymer protonation leads to the formation of several non-B-DNA structures, including left-handed Z conformation.

【 授权许可】

Unknown