Nielsen P E, Møllegaard N E
Department of Biochemistry B, Panum Institute, Copenhagen, Denmark.
J Mol Recognit. 1996 May-Jun;9(3):228-32. doi: 10.1002/(SICI)1099-1352(199605)9:3%3C228::AID-JMR243%3E3.0.CO;2-R.
The uranyl(VI) ion, UO(2)2+, cleaves yeast tRNA(Phe) both thermally and photochemically. Photochemical cleavage takes place at all positions but exhibits maxima at G10, G18, G30, A38, C49 and A62. Furthermore, in the presence of stoichiometric concentrations of citrate, the cleavage is generally suppressed except that strong cleavage at positions G10 and C48-U50 persists, indicating the presence of a high-affinity metal-ion binding site. It is proposed that these photocleavage sites reflect the tertiary structure of the yeast tRNA(Phe) molecule in terms of D-loop/T-loop interaction and anticodon loop conformation and that uranyl-mediated photocleavage of RNA may be used as a probe of RNA tertiary structure, and in particular for identifying binding sites for divalent metal ions. Thus a high-affinity metal-ion binding site is inferred in the "central pocket" formed by the D-loop, and the acceptor stem.
六价铀酰离子UO₂²⁺能通过热裂解和光化学裂解作用切割酵母苯丙氨酸转运核糖核酸（tRNA(Phe)）。光化学裂解作用在所有位置均可发生，但在G10、G18、G30、A38、C49和A62位置表现出最大值。此外，在化学计量浓度的柠檬酸盐存在的情况下，除了G10和C48 - U50位置的强烈裂解仍然存在外，裂解作用总体上受到抑制，这表明存在一个高亲和力的金属离子结合位点。有人提出，这些光裂解位点从D环/T环相互作用和反密码子环构象方面反映了酵母tRNA(Phe)分子的三级结构，并且铀酰介导的RNA光裂解作用可以用作RNA三级结构的探针，特别是用于识别二价金属离子的结合位点。因此，在由D环和受体茎形成的“中央口袋”中推断出一个高亲和力的金属离子结合位点。
