9.B.259.   The Uncharacterized Archaeal/Bacterial Protein-1 (UABP1) Family 

The UBP9 family consists mostly of proteins of about 200 - 250 aas with 6 TMSs, but several have more than 6 TMSs, and a few have less.  They derive from uncultured and cultured bacteria as well as archaea. Those in subfamily 2 may be parts of histidine sensor kinases. In this respect, and with appreciable sequence similarity, they resemble some members of the family with TC# 9.B.238.2. These two families include the sensor domain of sensor kinases at their C-termini, and this domain comprises a superfamily not listed in TCDB because it is not related to transport.