Structure and mechanism of a metal-sensing regulatory RNA
Dann III, C.E., Wakeman, C.A., Sieling, C.L., Baker, S.C., Irnov, I., Winkler, W.C.(2007) Cell 130: 878-892
- PubMed: 17803910 
- DOI: https://doi.org/10.1016/j.cell.2007.06.051
- Primary Citation of Related Structures:  
2QBZ - PubMed Abstract: 
Organisms maintain the correct balance of intracellular metals primarily through metal-sensing proteins that control transport and storage of the target ion(s). Here, we reveal the basis of metal sensing and genetic control by a metalloregulatory RNA. Our data demonstrate that a previously uncharacterized orphan riboswitch, renamed the "M-box," is a divalent metal-sensing RNA involved in Mg(2+) homeostasis. A combination of genetic, biochemical, and biophysical techniques demonstrate that Mg(2+) induces a compacted tertiary architecture for M-box RNAs that regulates the accessibility of nucleotides involved in genetic control. Molecular details are provided by crystallographic structure determination of a Mg(2+)-bound M-box RNA. Given the distribution of this RNA element, it may constitute a common mode for bacterial metal ion regulation, and its discovery suggests the possibility of additional RNA-based metal sensors in modern and primordial organisms.
Organizational Affiliation: 
Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.