Kolk M H, van der Graaf M, Wijmenga S S, Pleij C W, Heus H A, Hilbers C W
Nijmegen SON Research Center for Molecular Structure, Design and Synthesis, Laboratory of Biophysical Chemistry, University of Nijmegen, Toernooiveld, 6525 ED Nijmegen, The Netherlands.
Science. 1998 Apr 17;280(5362):434-8. doi: 10.1126/science.280.5362.434.
Pseudoknot formation folds the 3' ends of many plant viral genomic RNAs into structures that resemble transfer RNA in global folding and in their reactivity to transfer RNA-specific proteins. The solution structure of the pseudoknotted T arm and acceptor arm of the transfer RNA-like structure of turnip yellow mosaic virus (TYMV) was determined by nuclear magnetic resonance (NMR) spectroscopy. The molecule is stabilized by the hairpin formed by the 5' end of the RNA, and by the intricate interactions related to the loops of the pseudoknot. Loop 1 spans the major groove of the helix with only two of its four nucleotides. Loop 2, which crosses the minor groove, interacts closely with its opposing helix, in particular through hydrogen bonds with a highly conserved adenine. The structure resulting from this interaction between the minor groove and single-stranded RNA at helical junctions displays internal mobility, which may be a general feature of RNA pseudoknots that regulates their interaction with proteins or other RNA molecules.
假结形成将许多植物病毒基因组RNA的3'末端折叠成在整体折叠以及对tRNA特异性蛋白的反应性方面类似于转运RNA的结构。芜菁黄花叶病毒（TYMV）的类tRNA结构的假结T臂和受体臂的溶液结构通过核磁共振（NMR）光谱法确定。该分子通过RNA 5'末端形成的发夹以及与假结环相关的复杂相互作用而稳定。环1仅用其四个核苷酸中的两个跨越螺旋的大沟。穿过小沟的环2与其相对的螺旋紧密相互作用，特别是通过与高度保守的腺嘌呤形成氢键。在螺旋连接处小沟与单链RNA之间这种相互作用产生的结构显示出内部流动性，这可能是RNA假结调节其与蛋白质或其他RNA分子相互作用的一个普遍特征。
