2.A.26 The Branched Chain Amino Acid:Cation Symporter (LIVCS) Family
Characterized members of this family transport all three of the branched chain aliphatic amino acids (leucine (L), isoleucine (I) and valine (V)). They 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.
The generalized transport reaction is:
[L, I or V] (out) + [Na+ or H+] (out) → [L, I or V] (in) + [Na+ or H+] (in).
References associated with 2.A.26 family:
Braun, P.R., H. Al-Younes, J. Gussmann, J. Klein, E. Schneider, and T.F. Meyer. (2008). Competitive inhibition of amino acid uptake suppresses chlamydial growth: involvement of the chlamydial amino acid transporter BrnQ. J. Bacteriol. 190: 1822-1830. 18024516
Reizer, J., A. Reizer and M.H. Saier, Jr. (1994). A functional superfamily of sodium/solute symporters. Biochim. Biophys. Acta 1197: 133-166. 8031825
Stucky, K., A. Hagting, J.R. Klein, H. Matern, B. Henrich, W.N. Konings and R. Plapp (1995). Cloning and characterization of brnQ, a gene encoding a low-affinity, branched-chain amino acid carrier in Lactobacillus delbruckii subsp. lactis DSM7290. Mol. Gen. Genet. 249: 682-690. 8544834
Tauch, A., T. Hermann, A. Burkovski, R. Krämer, A. Pühler and J. Kalinowski (1998). Isoleucine uptake in Corynebacterium glutamicum ATCC 13032 is directed by the brnQ gene product. Arch. Microbiol. 169: 303-312. 9531631
