Water molecules in DNA recognition I: hydration lifetimes of trp operator DNA in solution measured by NMR spectroscopy.
Water molecules in DNA recognition I: hydration lifetimes of trp operator DNA in solution measured by NMR spectroscopy.
复制标题
DNA 识别中的水分子 I：通过 NMR 光谱测量溶液中 trp 操纵子 DNA 的水合寿命。
DOI：
10.1006/jmbi.1998.2033
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Otting,G
中科院分区：
文献类型：
--
作者：
Sunnerhagen,M;Denisov,VP;Venu,K;Bonvin,AM;Carey,J;Halle,B;Otting,G
本核磁共振研究通过测量水和DNA质子之间的分子间核Overhauser效应(NOE)以及水2H和17O共振的核磁弛豫色散(NMRD)，研究了与未络合的Trp操纵子DNA相关的水化水分子在溶液中的停留时间。这两种方法都表明，水合水分子在4℃时在亚纳秒的时间尺度上与主体水交换，没有证据表明水分子结合的停留时间更长。特别是，在Trp阻遏物/操纵子复合体中，界面水化部位的水分子在未复合的DNA中似乎不是动力学稳定的。对两个不同的Trp阻遏/操纵子复合体的晶体结构的分析表明，介导蛋白质和DNA之间特定接触的水分子的结构环境非常相似，而在未复合的Trp操纵子DNA双链的晶体结构中检测到的相应的水分子的位置却有更大的差异。因此，未复合的DNA靶标的水化特性似乎不太可能成为Trp抑制物/操纵子识别的主要决定因素。
The present NMR study investigates the residence times of the hydration water molecules associated with uncomplexed trp operator DNA in solution by measuring intermolecular nuclear Overhauser effects (NOE) between water and DNA protons, and the nuclear magnetic relaxation dispersion (NMRD) of the water2H and17O resonances. Both methods indicate that the hydration water molecules exchange with bulk water on the sub-nanosecond time scale at 4°C. No evidence was obtained for water molecules bound with longer residence times. In particular, the water molecules at the sites of interfacial hydration in the trp repressor/operator complex do not seem kinetically stabilized in the uncomplexed DNA. Analysis of the crystal structures of two different trp repressor/operator complexes shows very similar structural environments for the water molecules mediating specific contacts between the protein and the DNA, whereas much larger variations are observed for the location of corresponding water molecules detected in the crystal structure of an uncomplexed trp operator DNA duplex. Therefore, it appears unlikely that the hydration characteristics of the uncomplexed DNA target would be a major determinant of trp repressor/operator recognition.