Probable transporter of a GTP-driven Fe(2+) uptake system, might be able to transport Fe(2+) into or out of the cell (Probable). The crystallized N-terminal domain is a homodimer. The G protein domain (about resides 1-184) binds GDP faster and with higher affinity than GTP and releases GTP much faster than GDP. Release of bound nucleotide causes a rearrangement of GTP-binding domain G5, which may transmit information about the nucleotide-bound state from the G-domain to the transmembrane region of FeoB and effect Fe(2+) transport. Belongs to the TRAFAC class TrmE-Era-EngA-EngB-Septin-like GTPase superfamily. FeoB GTPase (TC 9.A.8) family.