Part of the ABC transporter complex BraDEFGC/C3 involved in transport of branched-chain amino acids Leu, Ile and Val (LIV). Essential for the development of bacteroids, the differentiated legume-symbiotic forms of this bacterium, and for the effective N(2) fixation by them. The complex is composed of two ATP-binding proteins (BraF and BraG), two transmembrane proteins (BraD and BraE) and a solute-binding protein (BraC or BraC3). Reduced uptake of amino acids Glu, Asp, Ala, Leu, Ile and Val by bacteroids that lack this gene and the genes aapJ and braC from the two ABC uptake systems of branched-chain amino acids. Pea plants inoculated with the triple mutant bacteroids are defective in symbiosis; the plants are yellow, have increased numbers of small pale pink root nodules, dry weights similar to uninoculated control plants and 30% acetylene reduction compared to plants inoculated with wild-type bacteroids. Belongs to the leucine-binding protein family.