通过中子散射研究的短DNA片段的溶液结构。

Solution structure of a short DNA fragment studied by neutron scattering.

作者信息

Lederer H, May R P, Kjems J K, Baer G, Heumann H

出版信息

Eur J Biochem. 1986 Nov 17;161(1):191-6. doi: 10.1111/j.1432-1033.1986.tb10141.x.

DOI:10.1111/j.1432-1033.1986.tb10141.x

Abstract

The solution structure of a DNA fragment of 130 base pairs and known sequence has been investigated by neutron small-angle scattering. In 0.1 M NaCl, the overall structure of the DNA fragment which contains the strong promoter A1 of the Escherichia coli phage T7 agrees with that expected for B-DNA. The neutron scattering curve is well fitted by that of a rigid rod with a length of 44 nm and a diameter of 2 nm. The results were confirmed by quasi-elastic light scattering and analytical centrifugation. The neutron measurements in H2O and D2O buffer reveal a cross-sectional inhomogeneity not detected by X-ray small-angle scattering. This inhomogeneity is caused by the hydration layer around the DNA core and not by the helical structure. The primary solvent shell has a density increased by at least 4-9% compared to bulk water.

摘要

通过中子小角散射研究了一个130个碱基对且序列已知的DNA片段的溶液结构。在0.1M NaCl中，包含大肠杆菌噬菌体T7强启动子A1的DNA片段的整体结构与B-DNA预期结构相符。中子散射曲线与长度为44nm、直径为2nm的刚性棒的散射曲线拟合良好。结果通过准弹性光散射和分析超速离心得到证实。在H2O和D2O缓冲液中的中子测量揭示了X射线小角散射未检测到的横截面不均匀性。这种不均匀性是由DNA核心周围的水化层引起的，而非螺旋结构。与本体水相比，主要溶剂壳的密度增加了至少4-9%。