Effects of spermidine and hexaamminecobalt(III) on thymine imino proton exchange.
Effects of spermidine and hexaamminecobalt(III) on thymine imino proton exchange.
复制标题
亚精胺和六氨合钴 (III) 对胸腺嘧啶亚氨基质子交换的影响。
DOI：
10.1021/bi00477a008
复制
发表时间：
1990
期刊：
影响因子：
2.9
通讯作者：
Bloomfield,VA
中科院分区：
文献类型：
--
作者：
Plum,GE;Bloomfield,VA
生物化学系，明尼苏达大学，1479 Gortner大道，圣保罗，明尼苏达州55108接收1989年12月4日;修订的Mandarin pt接收1990年4月3日摘要：我们研究亚精胺和六氨合钴（III）结合对DNA碱基对动力学的影响。质子NMR谱线宽度测量用于监测聚[dA]-聚[dT]和交替共聚物[d（AT）] 15-[d（AT）] 15中胸腺嘧啶亚氨基质子的交换。我们采用Benight et al.（1988）的亚氨基质子交换的扩散效应，估计催化速率常数，并提取表观平衡常数之间的相互转换封闭（nonexchanging）和溶剂可及（可交换）状态的碱基对。该理论定性地描述了聚[dA]-聚[dT]中亚精胺催化的亚氨基质子交换的盐依赖性。对表观平衡常数的温度依赖性的van 't霍夫分析表明，亚精胺和六氨合钴（III）的结合降低了两种双链体中AT碱基对的非交换态和交换态之间的能量差。赖氨酸以及许多其他DNA结合分子稳定双螺旋以抵抗热变性（Mahler等人，1961;塔博尔，1962）。它们还可以促进顺从序列的二级结构的改变，最深刻的是右手B-DNA和左手Z-DNA之间的转变（Behe & Felsenfeld，1981; Rich等人，1984年）。
Department of Biochemistry, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55108 Received December 4, 1989; Revised Manuscript Received April 3, 1990 abstract: We examine the influence of spermidine and hexaamminecobalt (III) binding on DNA base pair dynamics. Proton NMR line-width measurements are used to monitor theexchange of the thymine imino proton in poly [dA]-poly [dT] and in the alternating copolymer [d (AT)] 15-[d (AT)] 15. We employ the treatment by Benight et al.(1988) of diffusion effects in imino protonexchange to estimate catalytic rate constants and to extract apparent equilibrium constants for the interconversion between closed (nonex-changing) and solvent-accessible (exchangeable) states of the base pairs. The salt dependence of the spermidine-catalyzed imino proton exchange in poly [dA]-poly [dT] is qualitatively described by this theory, van’t Hoff analysis of the temperature dependence of the apparent equilibrium constants suggests that the binding of spermidine and hexaamminecobalt (III) lowers the energy difference between the nonexchanging and exchanging states of the AT base pair in both duplexes.] R> lyamines, as well as many other DNA binding molecules, stabilize the double helix against thermal denaturation (Mahler et al., 1961; Tabor, 1962). They may also promote alterations of the secondary structure of amenable sequences, the most profound being the transition between right-handed B-DNA and left-handed Z-DNA (Behe & Felsenfeld, 1981; Rich et al., 1984).