核磁共振光谱法研究锤头状核酶中A9/G10.1位点金属离子的作用

NMR spectroscopic investigations of the roles of the metal ion at A9/G10.1 site in hammerhead ribozymes.

作者信息

Tanaka Yoshiyuki, Kasai Yasuhiro, Morita Eugene H, Kojima Chojiro, Toyozawa Atsushi, Yamasaki Kazuhiko, Taira Kazunari, Kondo Yoshinori

机构信息

Graduate School of Pharmaceutical Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Japan.

出版信息

Nucleic Acids Res Suppl. 2003(3):45-6. doi: 10.1093/nass/3.1.45.

DOI:10.1093/nass/3.1.45

PMID:14510372

Abstract

Most hammerhead ribozymes have metal ion-binding sequences which are composed of the sheared type G12-A9 pair and the G10.1-C11.1 base-pair. However, in some hammerhead ribozymes, the G10.1-C11.1 base-pair is substituted with the A10.1-U11.1 base-pair. Here, we studied structural features of this altered motif, by using NMR spectroscopy. For this purpose, we have synthesized a model RNA oligomer, UGAA10:rGGAUGAAUCC which mimics the altered motif. From a 2-dimensional (2D) 1H-1H NOESY spectrum, we were able to trace sequential NOEs between base protons and anomeric protons (H1'), and assigned these resonances. It was also found that G5 and A6 formed a sheared type G-A pair from the imino proton resonance of G5. Observation of the imino proton resonance of U4 suggested that U4 forms a base-pair with A7. These structural features of the altered motif of UGAA10 are similar to the common metal ion-binding motif with G12-A9 and G10.1-C11.1.

摘要

大多数锤头状核酶具有由剪切型G12 - A9碱基对和G10.1 - C11.1碱基对组成的金属离子结合序列。然而，在一些锤头状核酶中，G10.1 - C11.1碱基对被A10.1 - U11.1碱基对取代。在此，我们通过核磁共振光谱研究了这种改变基序的结构特征。为此，我们合成了一个模拟改变基序的RNA寡聚体模型UGAA10:rGGAUGAAUCC。从二维（2D）1H - 1H NOESY谱中，我们能够追踪碱基质子和异头质子（H1'）之间的序列核Overhauser效应（NOE），并对这些共振进行了归属。从G5的亚氨基质子共振还发现G5和A6形成了剪切型G - A碱基对。对U4的亚氨基质子共振的观察表明U4与A7形成碱基对。UGAA10改变基序的这些结构特征与具有G12 - A9和G10.1 - C11.1的常见金属离子结合基序相似。