title: Characterization of a novel prokaryotic GDP dissociation inhibitor domain from the G protein coupled membrane protein FeoB.
abstract: The FeoB family of membrane embedded G proteins are involved with high affinity Fe(II) uptake in prokaryotes. Here, we report that FeoB harbors a novel GDP dissociation inhibitor-like domain that specifically stabilizes GDP-binding through an interaction with the switch I region of the G protein. We show that the stabilization of GDP binding is conserved between species despite a high degree of sequence variability in their guanine nucleotide dissociation inhibitor (GDI)-like domains, and demonstrate that the presence of the membrane embedded domain increases GDP-binding affinity roughly 150-fold over the level accomplished by action of the GDI-like domain alone. To our knowledge, this is the first example for a prokaryotic GDI, targeting a bacterial G protein-coupled membrane process. Our findings suggest that Fe(II) uptake in bacteria involves a G protein regulatory pathway reminiscent of signaling mechanisms found in higher-order organisms.
authors: Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, PO Box 208024, New Haven, CT 06520-8024, USA.
authors: Edward T
authors: ET
authors: Eng
authors: Amir R
authors: AR
authors: Jalilian
authors: Krasimir A
authors: KA
authors: Spasov
authors: Vinzenz M
authors: VM
authors: Unger
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D027682:Cation Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000737:chemistry*; D006153:Guanosine Diphosphate / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins; C470580:FeoB protein, E coli; D020730:Guanine Nucleotide Dissociation Inhibitors; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D006153:Guanosine Diphosphate; D019204:GTP-Binding Proteins