Structural basis of novel interactions between the small-GTPase and GDI-like domains in prokaryotic FeoB iron transporter.
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.
Hattori
Motoyuki
M
Department of Basic Medical Sciences, Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo, Japan.
Jin
Yaohua
Y
Nishimasu
Hiroshi
H
Tanaka
Yoshiki
Y
Mochizuki
Masahiro
M
Uchiumi
Toshio
T
Ishitani
Ryuichiro
R
Ito
Koichi
K
Nureki
Osamu
O
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
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