Structural basis of GDP release and gating in G protein coupled Fe2+ transport.
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.
Guilfoyle
Amy
A
Centenary Institute, Sydney, New South Wales, Australia.
Maher
Megan J
MJ
Rapp
Mikaela
M
Clarke
Ronald
R
Harrop
Stephen
S
Jormakka
Mika
M
D001665:Binding Sites; D001692:Biological Transport; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D008958:Models, Molecular; D011487:Protein Conformation; D015398:Signal Transduction
D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins; C470580:FeoB protein, E coli; D006153:Guanosine Diphosphate; D007501:Iron; D019204:GTP-Binding Proteins