Nissen P, Ippolito J A, Ban N, Moore P B, Steitz T A
Department of Molecular Biophysics and Biochemistry, Yale University and Howard Hughes Medical Institute, New Haven, CT 06520-8114, USA.
Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):4899-903. doi: 10.1073/pnas.081082398. Epub 2001 Apr 10.
Analysis of the 2.4-A resolution crystal structure of the large ribosomal subunit from Haloarcula marismortui reveals the existence of an abundant and ubiquitous structural motif that stabilizes RNA tertiary and quaternary structures. This motif is termed the A-minor motif, because it involves the insertion of the smooth, minor groove edges of adenines into the minor groove of neighboring helices, preferentially at C-G base pairs, where they form hydrogen bonds with one or both of the 2' OHs of those pairs. A-minor motifs stabilize contacts between RNA helices, interactions between loops and helices, and the conformations of junctions and tight turns. The interactions between the 3' terminal adenine of tRNAs bound in either the A site or the P site with 23S rRNA are examples of functionally significant A-minor interactions. The A-minor motif is by far the most abundant tertiary structure interaction in the large ribosomal subunit; 186 adenines in 23S and 5S rRNA participate, 68 of which are conserved. It may prove to be the universally most important long-range interaction in large RNA structures.
对来自嗜盐栖热放线菌的大核糖体亚基的2.4埃分辨率晶体结构分析表明，存在一种丰富且普遍存在的结构基序，可稳定RNA的三级和四级结构。这种基序被称为A- minor基序，因为它涉及腺嘌呤平滑的小沟边缘插入相邻螺旋的小沟中，优先插入C-G碱基对处，在那里它们与这些碱基对的一个或两个2'-OH形成氢键。A- minor基序可稳定RNA螺旋之间的接触、环与螺旋之间的相互作用以及连接点和紧密转角的构象。结合在A位点或P位点的tRNA的3'末端腺嘌呤与23S rRNA之间的相互作用就是具有功能意义的A- minor相互作用的例子。A- minor基序是大核糖体亚基中迄今为止最丰富的三级结构相互作用；23S和5S rRNA中有186个腺嘌呤参与其中，其中68个是保守的。它可能被证明是大型RNA结构中普遍最重要的长程相互作用。
