Crystal structure of a novel RNA motif that allows for precise positioning of a single metal ion.
Kanazawa, H., Kondo, J.(2017) J Inorg Biochem 176: 140-143
- PubMed: 28898762 
- DOI: https://doi.org/10.1016/j.jinorgbio.2017.08.029
- Primary Citation of Related Structures:  
5XWG - PubMed Abstract: 
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 2+ 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 2+ , Mn 2+ , Co 2+ , Zn 2+ , Ba 2+ , Pb 2+ and Cd 2+ , 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.
Organizational Affiliation: 
Graduate School of Science and Technology, Sophia University, Tokyo 102-8554, Japan.