The outer membrane component of an inducible organic solvent efflux pump. Involved in export of toluene and styrene but not of m-xylene, propylbenzene or ethylbenzene. Is not involved in antibiotic or AMP efflux. The ttgDEF operon is induced in the presence of toluene and styrene, but not m-xylene. Belongs to the outer membrane factor (OMF) (TC 1.B.17) family. Truncated N-terminus.