特定和非特定的金属离子-核酸相互作用在水性/固体界面与腺素,胆氨酸,关氨酸和氨酸寡合体功能化
Joseph G Holland1, Jessica N Malin, David S Jordan
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Journal of the American Chemical Society
|February 5, 2011
概括
这项研究量化了离子 (Mg2+) 与DNA结合的数量. 研究人员发现Mg2+离子在DNA链中均分布,特定的结合强度因核基而异.
科学领域:
- 生物物理化学 生物物理化学
- 分子生物物理学 分子生物物理学
- 核酸化学的核酸化学
背景情况:
- 对于分子生物学和纳米技术来说,了解阴子-DNA相互作用至关重要.
- 之前用于量化与DNA结合的阴离子的方法通常需要标签或间接测量.
- 离子 (Mg2+) 在DNA结构和功能中的作用很重要,但需要精确的量化.
研究的目的:
- 直接量化Mg2+离子与DNA结合的数量和热力学21-mers在接口.
- 为了确定Mg2+对单个核基 (腺素,胆氨酸,关氨酸,细胞氨酸) 的特定结合能量.
- 调查非特异性相互作用与DNA骨干对Mg2+结合的贡献.
主要方法:
- 使用非线性光学测量来量化没有标签的Mg2+结合.
- DNA21-mers与合的/水接口有共连接.
- 实验是在受控的pH (7) 和盐度 (10mM NaCl) 进行的.
主要成果:
- 确定Mg2+与腺因,胆氨酸,关氨酸和细胞因的总相互作用能量分别为-10.0 ± 0.3,-11.2 ± 0.3, -14.0 ± 0.4和 -14.9 ± 0.4kJ/mol.
- 与酸盐和糖骨干的非特异性相互作用为每个结合的Mg2+离子贡献了-21.0 ± 0.6kJ/mol.
- 氨酸和氨酸每21米尔结合3个Mg2+离子,而细胞氨酸和关氨酸每21米尔结合11个Mg2+离子.
结论:
- 特定和非特定的Mg2+结合贡献是附加的,这表明离子在DNA上的分布是均的.
- 这些发现提供了直接的,无标签的量化Mg2+与DNA结合的界面.
- 这项工作为Mg2+ - 核基和Mg2+ - 脊柱相互作用提供了精确的热力学数据.
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