High affinity nickel transporters involved in the incorporation of nickel into H2-uptake hydrogenase [2] and urease [3] enzymes. Essential for the expression of catalytically active hydrogenase and urease. Ion uptake is dependent on proton motive force. HoxN in Alcaligenes eutrophus is thought to be an integral membrane protein with seven transmembrane helices [4]. The family also includes a cobalt transporter.

1: Cloning, sequencing, and expression of thermophilic Bacillus sp. strain TB-90 urease gene complex in Escherichia coli. Maeda M, Hidaka M, Nakamura A, Masaki H, Uozumi T; J Bacteriol 1994;176:432-442. PMID:8288539

2: Bacterial genes involved in incorporation of nickel into a hydrogenase enzyme. Fu C, Javedan S, Moshiri F, Maier RJ; Proc Natl Acad Sci U S A 1994;91:5099-5103. PMID:8197192

3: Helicobacter pylori nickel-transport gene nixA: synthesis of catalytically active urease in Escherichia coli independent of growth conditions. Mobley HL, Garner RM, Bauerfeind P; Mol Microbiol 1995;16:97-109. PMID:7651142

4: A topological model for the high-affinity nickel transporter of Alcaligenes eutrophus. Eitinger T, Friedrich B; Mol Microbiol 1994;12:1025-1032. PMID:7934894