对于大肠杆菌NikRR的Ni (II) 响应DNA结合活性至关重要
Sheila C Wang1, Yanjie Li, Carol V Robinson
1Department of Chemistry, University of Toronto, Ontario, Canada M5S 3H6.
Journal of the American Chemical Society
|January 22, 2010
概括
(K+) 对于大肠杆菌的NikR转录因子来说是必不可少的,以对 (Ni(II)) 的反应来结合DNA. 没有K+,NikR失去调节基因表达的能力,突出K+作为关键的激活剂.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 大肠杆菌NikR是一种依赖 (Ni(II)) 的转录因子,调节离子载体的产生.
- 一个先前确定的晶体结构显示了 (K+) 结合点在Ni(II) -NikR-DNA复合体中,但其功能作用是未知的.
研究的目的:
- 为了阐明 (K+) 结合部位在Ni(II) -NikR-DNA复合体中的功能意义.
- 调查K+在Ni (II) 响应DNA结合中的作用和NikR转录因子的特异性.
主要方法:
- 在K+配体残留物的位点定向突变发生.
- 在体外试验测试以评估在K+存在或不存在的情况下的DNA结合亲和力和特异性.
- 阴子交换实验探测K+依赖性.
主要成果:
- 一个K+连接体残留物的突变显著损害了NikR的DNA结合亲和力和对Ni的特异性.
- 删除K+完全取消了对Ni (II) 响应的DNA结合,而其添加恢复了活性.
- 用氨酸替换一个关键的K+配体 (Asp34) 缓解了K+依赖.
结论:
- (K+) 是一个关键的结构部件,需要通过NIKR转录因子激活Ni(II) 响应DNA结合.
- 在调节尼克R与DNA相互作用方面,K+起着至关重要的作用,在的存在下,它影响了亲和力和特异性.
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