Escherichia coli has an iron(II) transport system (feo) which may make an important contribution to the iron supply of the cell under anaerobic conditions [1]. FeoB has been identified as part of this transport system. FeoB is a large 700-800 amino acid integral membrane protein. The N terminus contains a P-loop motif suggesting that iron transport may be ATP dependent [1].

1: Characterization of the ferrous iron uptake system of Escherichia coli. Kammler M, Schon C, Hantke K; J Bacteriol 1993;175:6212-6219. PMID:8407793