9.B.381.  The DUF2755 or YaiY (DUF2755) Family 

This family consists of proteins with about 100 aas and  2 TMSs, or about 50 aas and 1 TMS.  Their functions are not known.  It is not established that the 2 TMS proteins were derived by duplication of a gene encoding a 1 TMS protein.