9.B.108 The Putative 7/8 TMS Porter (P7/8P) Family

Memberes of the P7/8P family usually exhibit 7 or 8 TMS and have lengths of 200 - 260 aas.  Functional data are currently lacking.  However, one family member, 9.B.108.1.4, gives a score of e^-6 with 9.B.2.1.7, a putative CAAX2 protease with residues 25 - 207 (TMSs 1-6 or 7 (TMS 7 is very small) of the former protein aligning with residues 27 - 206 (TMSs 1-6) of the latter.  Interestingly, only TMSs 7 - 11 in 9.B.2.1.7 align with other members of the CAAX2 family, and the N-terminal 6 TMSs of 9.B.2.1.7 align with TMSs 1-6 in three members of the MFS (2.A.1.2.5, 1.81 and 21.4).  This suggests that 9.B.2.1.7 is a hybrid protein.  Thus, the N-terminal 6 TMSs of 9.B.2.1.7 and P7/8P family members may be derived from the basic 6 TMS repeat unit of MFS porters.