TCDB is operated by the Saier Lab Bioinformatics Group

9.B.272.  The Uncharacterized Protein from Uncultivated Bacteria-9 (UPUB9) Family

This family includes small protein of about 170 to 210 aas, usually with 5 TMSs.  They are found exclusively in uncultured bacteria. However, with an iteration with NCBI Psi-Blast, the dominant proteins that come up are amino acid transport membrane proteins of the ABC superfamily with TC# 3.A.1.3.  These integral membrae ABC proteins show variable numbers of TMSs, but many have 5 TMSs.