Structural basis of GDP release and gating in G protein coupled Fe2+ transport

EMBO J. 2009 Sep 2;28(17):2677-85. doi: 10.1038/emboj.2009.208. Epub 2009 Jul 23.


G proteins are key molecular switches in the regulation of membrane protein function and signal transduction. The prokaryotic membrane protein FeoB is involved in G protein coupled Fe(2+) transport, and is unique in that the G protein is directly tethered to the membrane domain. Here, we report the structure of the soluble domain of FeoB, including the G protein domain, and its assembly into an unexpected trimer. Comparisons between nucleotide free and liganded structures reveal the closed and open state of a central cytoplasmic pore, respectively. In addition, these data provide the first observation of a conformational switch in the nucleotide-binding G5 motif, defining the structural basis for GDP release. From these results, structural parallels are drawn to eukaryotic G protein coupled membrane processes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Biological Transport
  • Cation Transport Proteins / chemistry*
  • Cation Transport Proteins / metabolism
  • Cytoplasm / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / metabolism
  • GTP-Binding Proteins / chemistry*
  • GTP-Binding Proteins / metabolism
  • Guanosine Diphosphate / chemistry
  • Guanosine Diphosphate / metabolism*
  • Iron / metabolism*
  • Models, Molecular
  • Protein Conformation
  • Signal Transduction


  • Cation Transport Proteins
  • Escherichia coli Proteins
  • FeoB protein, E coli
  • Guanosine Diphosphate
  • Iron
  • GTP-Binding Proteins