Part of the ABC transporter complex RbsABC involved in ribose import. Binds ribose. The complex is composed of an ATP-binding protein (RbsA), two transmembrane proteins (RbsC) and a solute-binding protein (RbsB) (By similarity). 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. Belongs to the bacterial solute-binding protein 2 family.