This model represents the fused enzyme II B and C components of the trehalose-specific PTS sugar transporter system. Trehalose is converted to trehalose-6-phosphate in the process of translocation into the cell. These transporters lack their own IIA domains and instead use the glucose IIA protein (IIAglc or Crr). The exceptions to this rule are Staphylococci and Streptococci which contain their own A domain as a C-terminal fusion. This family is closely related to the sucrose transporting PTS IIBC enzymes and the B and C domains of each are described by subfamily-domain level TIGRFAMs models (TIGR00826 and TIGR00852, respectively). In E. coli, B. subtilis and P. fluorescens the presence of this gene is associated with the presence of trehalase which degrades T6P to glucose and glucose-6-P. Trehalose may also be transported (in Salmonella) via the mannose PTS or galactose permease systems, or (in Sinorhizobium, Thermococcus and Sulfolobus, for instance) by ABC transporters.
Jiyao W et al.(2023). "The conserved domain database in 2023.",