TCDB is operated by the Saier Lab Bioinformatics Group

9.B.193 The Proteobacterial 8 TMS Membrane Protein (P8MP) Family 

The P8MP protein is a relatively small family consisting largely of alpha-proteobacteerial proteins with about 350 to 550 aas and 8 putative TMSs.  They are not recognized by CDD.  These protein might be related to the SSS family (2.A.21), but this possibility has not been tested.