Involved in a multicomponent binding-protein-dependent transport system for glycine betaine. The complex is composed of two ATP-binding proteins (OpuAA), two transmembrane proteins (OpuAB) and a solute-binding protein (OpuAC) (PubMed:7622480). Interacts with FloT (PubMed:23651456). Present in detergent-resistant membrane (DRM) fractions that may be equivalent to eukaryotic membrane rafts; these rafts include proteins involved in signaling, molecule trafficking and protein secretion.