This family includes FeoA a small protein, probably involved in Fe2+ transport [1]. This presumed short domain is also found at the C-terminus of a variety of metal dependent transcriptional regulators. This suggests that this domain may be metal-binding. In most cases this is likely to be either iron or manganese.

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