title: Structural basis of novel interactions between the small-GTPase and GDI-like domains in prokaryotic FeoB iron transporter.
abstract: The FeoB family proteins are widely distributed prokaryotic membrane proteins involved in Fe(2+) uptake. FeoB consists of N-terminal cytosolic and C-terminal transmembrane domains. The N-terminal region of the cytosolic domain is homologous to small GTPase (G) proteins and is considered to regulate Fe(2+) uptake. The spacer region connecting the G and TM domains reportedly functions as a GDP dissociation inhibitor (GDI)-like domain that stabilizes the GDP-binding state. However, the function of the G and GDI-like domains in iron uptake remains unclear. Here, we report the structural and functional analyses of the FeoB cytosolic domain from Thermotoga maritima. The structure-based mutational analysis indicated that the interaction between the G and GDI-like domains is important for both the GDI and Fe(2+) uptake activities. On the basis of these results, we propose a regulatory mechanism of Fe(2+) uptake.
authors.affiliation: Department of Basic Medical Sciences, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Hattori
authors.forename: Yaohua
authors.initials: Y
authors.lastname: Jin
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishimasu
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Mochizuki
authors.forename: Toshio
authors.initials: T
authors.lastname: Uchiumi
authors.forename: Ryuichiro
authors.initials: R
authors.lastname: Ishitani
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Osamu
authors.initials: O
authors.lastname: Nureki
mesh_terms: D001665:Binding Sites; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D020559:Monomeric GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D020124:Thermotoga maritima / Q000201:enzymology* / Q000378:metabolism; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors
chemical_list: D027682:Cation Transport Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; D026901:Membrane Transport Proteins; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D007501:Iron; D020559:Monomeric GTP-Binding Proteins