This family consists of several bacterial ABC transporter proteins which are homologous to the EcsB protein of Bacillus subtilis. EcsB is thought to encode a hydrophobic protein with six membrane-spanning helices in a pattern found in other hydrophobic components of ABC transporters [1].

1: Molecular analysis of an operon in Bacillus subtilis encoding a novel ABC transporter with a role in exoprotein production, sporulation and competence. Leskela S, Kontinen VP, Sarvas M; Microbiology 1996;142:71-77. PMID:8581172