PTS_IIB_chitobiose_lichenan: subunit IIB of enzyme II (EII) of the N,N-diacetylchitobiose-specific and lichenan-specific phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS). In these systems, EII is either a lichenan- or an N,N-diacetylchitobiose-specific permease with two cytoplasmic domains (IIA and IIB) and a transmembrane channel IIC domain. In the chitobiose system, these subunits are expressed as separate proteins from chbA, chbB, and chbC of the chb operon (formerly the cel (cellulose) operon). In the lichenan system, these subunits are expressed from licA, licB, and licC of the lic operon. The lic operon of Bacillus subtilis is required for the transport and degradation of oligomeric beta-glucosides, which are produced by extracellular enzymes on substrates such as lichenan or barley glucan. The lic operon is transcribed from a gammaA-dependent promoter and is inducible by lichenan, lichenan hydrolysate, and cellobiose. The IIB domain fold includes a central four-stranded parallel open twisted beta-sheet flanked by alpha-helices on both sides. The seven major PTS systems with this IIB fold include chitobiose/lichenan, ascorbate, lactose, galactitol, mannitol, fructose, and a sensory system with similarity to the bacterial bgl system.
Jiyao W et al.(2023). "The conserved domain database in 2023.",