Branched chain amino acid–cation symporter
The branched chain amino acid:cation symporter family is a member of the APC superfamily. Characterized members of this family transport all three of the branched chain aliphatic amino acids, isoleucine and valine ). These proteins are found in Gram-negative and Gram-positive bacteria and function by a Na+ or H+ symport mechanism. They possess about 440 amino acyl residues and display 12 putative transmembrane helical spanners. As of early 2016, no crystal structures for members of the LIVCS family are available on RCSB.