Structure and mechanism of a metal-sensing regulatory RNA

Cell. 2007 Sep 7;130(5):878-92. doi: 10.1016/j.cell.2007.06.051.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 5' Untranslated Regions*
  • Antiporters / genetics
  • Antiporters / metabolism*
  • Bacillus subtilis / genetics
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Crystallography
  • Gene Expression Regulation, Bacterial*
  • Genes, Reporter
  • Homeostasis
  • Lac Operon
  • Magnesium Chloride / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Nucleic Acid Conformation
  • RNA, Bacterial / metabolism*
  • RNA, Messenger / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Regulatory Sequences, Ribonucleic Acid*
  • Transcription, Genetic*


  • 5' Untranslated Regions
  • Antiporters
  • Bacterial Proteins
  • MgtE protein, bacteria
  • RNA, Bacterial
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • Regulatory Sequences, Ribonucleic Acid
  • Magnesium Chloride

Associated data

  • PDB/2QBZ