Kanazawa Hiroki, Kondo Jiro
Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan.
Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan; Department of Materials and Life Sciences, Sophia University, Tokyo 102-8554, Japan.
J Inorg Biochem. 2017 Nov;176:140-143. doi: 10.1016/j.jinorgbio.2017.08.029. Epub 2017 Sep 21.
We have determined a crystal structure of an RNA duplex containing a novel metal-binding motif. The motif is composed of two sheared G○A base pairs, two unpaired A residues and four phosphate groups in close proximity. Four A residues make an A-A-A-A stacking column at the minor groove side and two G bases are highly inclined, thereby forming the pocket-shaped motif at the major groove side. In the present structure, a hydrated Sr ion exists in the pocket and binds to the O6 and N7 atoms of the two G bases and four phosphate groups. According to the previously-reported metal-binding properties to RNA molecules, many of divalent cations, such as Mg, Mn, Co, Zn, Ba, Pb and Cd, may bind to the motif. This metal-binding motif can be used as a modular building block that allows for precise positioning of a single metal ion in functional nucleic acid molecules.
我们已经确定了一种含有新型金属结合基序的RNA双链体的晶体结构。该基序由两个剪切的G○A碱基对、两个未配对的A残基和四个紧密相邻的磷酸基团组成。四个A残基在小沟侧形成一个A-A-A-A堆积柱，两个G碱基高度倾斜，从而在大沟侧形成袋状基序。在当前结构中，一个水合Sr离子存在于袋中，并与两个G碱基的O6和N7原子以及四个磷酸基团结合。根据先前报道的RNA分子的金属结合特性，许多二价阳离子，如Mg、Mn、Co、Zn、Ba、Pb和Cd，可能与该基序结合。这种金属结合基序可以用作模块化构建块，允许在功能性核酸分子中精确定位单个金属离子。
