DNA薄膜中的类分形图案、0%相对湿度下的B型以及抗自主DNA：一项红外研究

Fractal-like patterns in DNA films, B form at 0% relative humidity, and antiheteronomous DNA: an IR study.

作者信息

Sclavi B, Peticolas W L, Powell J W

机构信息

Department of Chemistry, Reed College, Portland, Oregon 97202.

出版信息

Biopolymers. 1994 Aug;34(8):1105-13. doi: 10.1002/bip.360340814.

DOI:10.1002/bip.360340814

PMID:8075390

Abstract

This report details the observation of (a) the intact double helix of DNA at 0% relative humidity in poly(dA).poly(dT) and poly(dA-dT).poly(dA-dT) films, (b) the fractal-like growth of DNA crystals in films of poly(dA).poly(dT), and (c) poly(dA).poly(dT) with adenines in the B form and thymines in the A form. Observation (a) is based on the behavior of the middle ir signature of double-helical base stacking, the 1714 cm-1 peak, at low water activity. This observation is modeled as a trapping of water in the polycrystalline part of these films. We interpret the glycosidic region of the middle ir spectra of the polycrystalline films of poly(dA).poly(dT) at 0% relative humidity to indicate that at least part of the adenine strand in is the B conformation and the thymine strand is in the A form, whereas previous assignments of poly(dA).poly(dT) films at 75% relative humidity indicated the opposite strand conformation assignment [E. Taillandier et al. (1987) Biochemistry, Vol. 26 p. 3361].

摘要

本报告详细阐述了以下观察结果

(a) 在聚（dA）·聚（dT）和聚（dA-dT）·聚（dA-dT）薄膜中，相对湿度为0%时DNA完整的双螺旋结构；(b) 在聚（dA）·聚（dT）薄膜中DNA晶体的类分形生长；(c) 聚（dA）·聚（dT）中腺嘌呤呈B型，胸腺嘧啶呈A型。观察结果(a)基于双螺旋碱基堆积的中红外特征（1714 cm-1峰）在低水活度下的行为。该观察结果被模拟为这些薄膜多晶部分中水分的捕获。我们解释了相对湿度为0%时聚（dA）·聚（dT）多晶薄膜的中红外光谱糖苷区，表明其中至少部分腺嘌呤链呈B构象，胸腺嘧啶链呈A型，而之前对相对湿度为75%的聚（dA）·聚（dT）薄膜的归属表明链构象相反 [E. Taillandier等人（1987年），《生物化学》，第26卷，第3361页]。