Probably part of the ABC transporter complex YxeMNO that could be involved in amino-acid import. May transport S-methylcysteine. The complex is composed of two ATP-binding proteins (YxeO), two transmembrane proteins (YxeN) and a solute-binding protein (YxeM). 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. More strongly expressed in the presence of methionine than in the presence of sulfate. Belongs to the bacterial solute-binding protein 3 family.