9.B.69 The Putative Cobalt Transporter (CbtAB) Family
The putative cobalt transporter family consists of two proteins, one (CbtA) of about 230 aas with 6 TMSs, and one (CbtB) of about 70 (60-150) residues, with a single putative TMS. CbtB is possibly a periplasmic or membrane anchored Co2+ binding protein. However, some of the larger homologues have the putative TMS at their C-termini. These proteins are encoded in operons that are subject to regulation by vitamin B12 (Rodionov et al., 2003). They are found in α- and γ-proteobacteria. Their functions are not established.
References associated with 9.B.69 family:
Rodionov, D.A., A.G. Vitreschak, A.A. Mironov, and M.S. Gelfand. (2003). Comparative genomics of the vitamin B12 metabolism and regulation in prokaryotes. J. Biol. Chem. 278: 41148-41159. 12869542