Permease that is involved in the transport across the cytoplasmic membrane of D-alanine, D-serine and glycine. D-alanine(in) + H(+)(in) = D-alanine(out) + H(+)(out) D-serine(out) + H(+)(out) = D-serine(in) + H(+)(in) glycine(in) + H(+)(in) = glycine(out) + H(+)(out) Belongs to the amino acid-polyamine-organocation (APC) superfamily. Amino acid transporter (AAT) (TC 2.A.3.1) family.