COMPARE 39K TRANSVERSE RELAXATION IN VITRO SOLUTIONS & IN CYTOPLASM OF E COLI

比较 39K 横向松弛体外解决方案

• 批准号: 6281614
• 负责人: M. THOMAS RECORD
• 金额: $ 0.06万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 1999-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6281614
• 关键词: biological products; biomaterials; biomedical resource; nuclear magnetic resonance spectroscopy; nucleic acids; proteins

The most abundant cation and osmolyte in the cytoplasm of E. coli, K+, has been used in studies of molecular interactions of DNA, proteins, ribosome and ions via 39K NMR. In our previous experiments, a large transverse relaxation rate of 39K has been observed in dense slurries of E. coli cells. Since the interaction of the K nucleus with the surrounding electric field gradient of the DNA dominants the 39K transverse relaxation in a K-DNA solution with little salt added, it was considered as the explanation for the 39K relaxation measured in vivo. However, the relaxation rate of 39K in DNA solutions, even with a very high concentration (i.e., physiological conditions), is much slower than that in vivo. Similar results were obtained for concentrated K-BSA and KCl solutions. The only in vitro solution that gives rise to the same large magnitude of the transverse relaxation rate as in vivo are ribosome solutions, the highly negative charged ribosome particles that have the most nucleic acids in the cell. Therefore, ribosome particles are considered as the key element that enhances the transverse relaxation of 39K in vivo. The similar characteristic of transverse relaxation was also observed in 23Na-ribosome solutions. These results require further experimental studies to confirm and to explore the molecular nature of the ribosome particle and K+, Na+-ribosome interactions. We will be using the DMX 400 spectrometer with the 10mm BB probe for both 39K and 23Na (a more sensitive nucleus) NMR studies.

大肠杆菌的细胞质中最丰富的阳离子和渗透剂， K+已被用于DNA的分子相互作用的研究 蛋白质，核糖体和离子通过39K NMR。 在我们以前的实验中 在密集中观察到了39K的较大横向松弛率 大肠杆菌细胞的浆液。 由于k核的相互作用 DNA主导的周围电场梯度 39k横向松弛在k-dna溶液中，添加了少量盐， 它被认为是测量39k放松的解释 体内。 但是，DNA溶液中39K的松弛率，甚至 浓度很高（即生理状况），为 比体内慢得多。 获得了类似的结果 浓缩K-BSA和KCL溶液。 唯一的体外解决方案 产生相同的横向松弛 体内的速率是核糖体溶液，高度负电荷 核糖体颗粒在细胞中具有最大的核酸。 因此，核糖体颗粒被认为是关键要素 增强体内39K的横向松弛。 类似 还观察到横向松弛的特征 23NA-核糖体溶液。 这些结果需要进一步的实验 确认和探索核糖体的分子性质的研究 粒子和k+，na+ - 横肌体相互作用。 我们将使用DMX 400光谱仪，具有10mm BB探头的39K和23NA（更多 敏感核）NMR研究。