This family represents five transmembrane helices that are normally found flanking (five either side) a pair of Pfam:PF02080 domains. This suggests that the paired regions form a ten helical structure, probably forming the pore, whereas the Pfam:PF02080) binds a ligand for export or regulation of the pore. Swiss:Q8L3K8 is described as a aspartate-alanine antiporter ([1]). In conjunction with Swiss:Q8L3K9 it forms a 'proton motive metabolic cycle catalysed by an aspartate-alanine exchange'. The general conservation of domain architecture in this family suggests that they are functional orthologues.

1: Plasmid-encoded asp operon confers a proton motive metabolic cycle catalyzed by an aspartate-alanine exchange reaction. Abe K, Ohnishi F, Yagi K, Nakajima T, Higuchi T, Sano M, Machida M, Sarker RI, Maloney PC; J Bacteriol 2002;184:2906-2913. PMID:12003930