多胺和镁与DNA的结合。

The binding of polyamines and magnesium to DNA.

Rowatt E, Williams R J

Department of Medical Microbiology, School of Pathology, University College and Middlesex School of Medicine, London, U.K.

J Inorg Biochem. 1992 May 1;46(2):87-97. doi: 10.1016/0162-0134(92)80012-k.

Abstract

The binding of spermine and Mg2+ to DNA has been investigated using the dye arsenazo III to measure unbound cations. 2. The apparent dissociation constant, Kd, of DNA for spermine has been found to be 7.4 +/- 3.9 x 10(-8) M and that for Mg2+, 6.5 +/- 3.3 x 10(-7) M. 3. Binding of spermine in the presence of 1 mM Mg2+ has been shown to have a Kd of about 4 x 10(-6) M. 4. Magnesium ion (2 mM) halves the concentration of spermine needed to cause DNA aggregation. 5. Spermidine binds to DNA with a similar affinity to spermine but 3,3'-iminobispropylamine and 1,5,9,13-tetra-azatridecane bind with a lower affinity. The naturally occurring polyamines thus have a higher affinity for DNA than the related polyamines which do not occur naturally. 6. Binding of spermine or spermidine to DNA alters the spectrophotometric absorbance of DNA at 260 nm.

摘要

已使用偶氮胂III染料来测量游离阳离子，以此研究精胺和Mg2+与DNA的结合情况。2. 已发现DNA对精胺的表观解离常数Kd为7.4±3.9×10(-8)M，对Mg2+的表观解离常数Kd为6.5±3.3×10(-7)M。3. 已表明在1 mM Mg2+存在的情况下，精胺的结合Kd约为4×10(-6)M。4. 镁离子（2 mM）可使导致DNA聚集所需的精胺浓度减半。5. 亚精胺与DNA的结合亲和力与精胺相似，但3,3'-亚氨基二丙胺和1,5,9,13-四氮杂十三烷的结合亲和力较低。因此，天然存在的多胺对DNA的亲和力高于非天然存在的相关多胺。6. 精胺或亚精胺与DNA的结合会改变DNA在260 nm处的分光光度吸收值。