EUROPIUM AS A FLUORESCENT-PROBE OF TRANSFER-RNA STRUCTURE
EUROPIUM AS A FLUORESCENT-PROBE OF TRANSFER-RNA STRUCTURE
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DOI：
10.1021/bi00678a014
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发表时间：
1975-01-01
期刊：
影响因子：
2.9
通讯作者：
KEARNS, DR
中科院分区：
文献类型：
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作者：
WOLFSON, JM;KEARNS, DR
铕 (III) 与大肠杆菌 tRNAfMet'Glu 和普通大肠杆菌 tRNA 的结合已通过使用铕 5Do-7Fi 发射的 4-硫代尿苷敏化以及先前报道的铕 5Do 态寿命的变化进行了研究（J. M. Wolf-son 和 DR Kearns (1974), J. Am. Chem. Soc. 96、3653）。前 3-4 个铕离子的结合是独立且连续的，大约比镁结合强 600 倍，并且结合位点位于 附近。有大量实验表明二价金属离子使 tRNA 稳定在生物活性构象中（Frescoet al.，1966）。镁满足二价阳离子的要求，但其他二价离子（Mn2+、Zn2+）甚至三价稀土离子可以在 tRNA 分子的氨酰化中替代 Mg2+（Igarashi 等人，1971；Kayne 和 Cohn，1972）。稀土离子特别适合用于研究溶液中多核苷酸的金属结合特性，因为它们的光学特性（吸收和发射光谱中带的相对强度、带位置、偏振、寿命、辐射和非辐射量子产率）对所连接的配体和基团的性质敏感（Gallagher，1964，1965）。人们对稀土离子更加感兴趣，因为它们目前被用于 tRNA 晶体的 X 射线衍射研究（Kim 等人）
The binding of europium (III) to Escherichia coli tRNAfMet'Glu and to unfractionated E. coli tRNA has been investigated by using the 4-thiouridine sensitization of europium 5Do—7Fi emission and changes in the lifetime of the 5Do state of europium reported earlier (J. M. Wolf-son and DR Kearns (1974), J. Am. Chem. Soc. 96, 3653). Binding of the first 3-4 europium ions is independent and sequential, approximately 600 times stronger than the magnesium binding, and the binding sites are located near theThere are a number of experiments which demonstrate that divalent metal ions stabilize tRNA in biologically ac-tive conformations (Frescoet al., 1966). Magnesium fulfills the divalent cation requirement, but other divalent ions (Mn2+, Zn2+) and even trivalent rare earth ions can substitute for Mg2+ in the aminoacylation of tRNA molecules (Igarashi et al., 1971; Kayne and Cohn, 1972). The rare earth ions are especially well suited for use in studying the metalbinding properties of polynucleotides in solution since their optical properties (relative intensity of bands in the absorption and emission spectra, band positions, polarization, lifetime, radiative and nonradiative quantum yields) are sensitive to the nature of attached lig-and groups (Gallagher, 1964, 1965). There is additional in-terest in the rare earth ions since they are currently being used in X-ray diffraction studies of tRNA crystals (Kim et