報文

NMR法によるRNAの構造決定におけるRDCを用いた二段階精密化の効果

Effect of Two Steps Refinement on the RNA Structure Determination by the NMR Method Using the Residual Dipolar Couplings

野村 祐介・坂本 泰一・河合 剛太
Yusuke NOMURA, Taiichi SAKAMOTO, and Gota KAWAI

近年，RNA の立体構造解析において，残余双極子相互作用（RDC）を解析することにより遠距離の情報を得ることができるようになった．本研究では，RDCの情報を効率よく加えられるように精密化方法を検討した．その結果，１段階の精密化ではRDCのr.m.s.d. が2.14 Hzであったのに対し，２段階の精密化では1.71 Hzとなり，構造計算が良く収束することがわかった．

As is the case with protein, structure is also important for biological functions of RNA, and many RNA structures were already determined by NMR techniques. However, it is difficult to determine the structures of larger RNAs containing bulge and/or internal loop by NMR method that relies on short-range distance and torsion angle restraints. Recently, long-range angular restraints derived from residual dipolar coupling (RDC) were used to improve the global precision of the structure. In the present study, we applied the two steps refinement method, which was introduced by Leeper and Varani, to determine the solution structure of a model RNA that contains a bulge. It was found that the average of RDC r.m.s.d. values for structures obtained by the two steps refinement was 1.71 Hz whereas that by the conventional single refinement was 2.14 Hz. Thus, this technique is useful for the structure determination of RNAs using the RDC restraints.

Keywords:NMR, RNA, RDC