| TCID | Name | Domain | Kingdom/Phylum | Protein(s) |
|---|---|---|---|---|
|
4.A.3.1.1 | Lactose (Lac) porter, LacEF (Kowolik and Hengstenberg 1998). This system is 87% identical to the LacEF ortholog in Streptococcus mutans (Rosey and Stewart 1992). | Bacteria |
Bacillota | Lactose (Lac) IICB-IIA complex of Staphylococcus aureus IIA (LacF) (P02909) IIBC (LacE) (P11162) |
|
4.A.3.1.2 | Bacteria |
Bacillota | ||
|
4.A.3.1.3 | Lactose PTS group translocator #2, IIA/IICB (Francl et al. 2012). | Bacteria |
Bacillota | Lactose PTS porter #2 of Lactobacillus gasseri |
|
4.A.3.2.1 | N,N'-diacetylchitobiose (Chb) porter (also transports cellobiose; Kachroo et al., 2007). | Bacteria |
Pseudomonadota | N,N'-diacetylchitobiose (Chb) IIC-IIB-IIA complex of E. coli IIA (ChbA), spP17335 IIB (ChbB), spP17409 IIC (ChbC), spP17334 |
|
4.A.3.2.2 | Lichenan oligosaccharide (Lic) porter: LicA-LicB-LicC of 110, 102 and 452 aas, respectively. Functions with LicH, a P-β-glucosidase (P46320). | Bacteria |
Bacillota | Lichenan oligosaccharide (Lic) IIC-IIB-IIA complex of Bacillus subtilis IIA (LicA), spP46319 IIB (LicB), spP46318 IIC (LicC), spP46317 |
|
4.A.3.2.3 | N,N'-diacetylchitobiose porter, ChbABC | Bacteria |
Spirochaetota | N,N'diacetylchitobiose (Chb) IIC-IIB-IIA complex of Borrelia burgdorferi IIA (ChbA), AAC66323 IIB (ChbB), AAC66322 IIC (ChbC), AAC66324 |
|
4.A.3.2.4 | The cellobiose-specific (PtcA-PtcB-CelB) porter (Kowalczyk et al., 2008 ). | Bacteria |
Bacillota | PtcA-PtcB-CelB of Lactococcus lactis: CelB (C)(Q9CJ32) PtcB (B)(Q9CIF0) PtcA (A)(Q9CIE9) |
|
4.A.3.2.5 | The N,N' -diacetylchitobiose Enzyme II (Toratani et al., 2008) (>80% identical to the E. coli enzyme (4.A.3.2.1)). The IIA protein is the Serratia glucose IIA which is nearly identical to the E. coli IIAGlc (Crr). | Bacteria |
Pseudomonadota | The N,N' -diacetylchitobiose Enzyme II of Serratia marcescens IIA (ChbA) - Q8L3C4 IIB (ChbB) - Q8L3C3 IIC (ChbC) - Q8L3C2 |
|
4.A.3.2.6 | Glucosamine β(1→4) glucosamine (GlcN)2 (glucosamine dimer) transporter, VC1281-1283 (IIB; IIC; IIA, respectively) (Meibom et al., 2004) | Bacteria |
Pseudomonadota | (GlcN)2 transporter of Vibrio cholerae (IIA-IIB-IIC) IIB (Q9KSH5) IIA (Q9KSH3) IIC (Q9KSH4) |
|
4.A.3.2.7 | N,N'-diacetylchitobiose (cellobiose) PTS permease, CelABC (IIABC). Essential for normal virulence and biofilm formation by K. pneumoniae which causes pyogenic liver abscesses (Wu et al. 2012). 88% identical to the diacetylchitobiose II (4.A.3.2.1) of E. coli. These two proteins are probably orthologous. | Bacteria |
Pseudomonadota | CelABC of Klebsiella pneumoniae |
|
4.A.3.2.8 | N-, N'-diacetylchitobiose PTS permease, IIABCChb (Also called IIABCCel for cellbiose). The crystal structure of the 10 TMS IIC membrane component has been determined by x-ray crystallography (Cao et al. 2011). | Bacteria |
Bacillota | ChbIIABC of Bacillus cereus ChbA (CelA); IIB (100 aas) (Q72XP9) ChbB (CelB); IIC (433 aas) (Q72XQ0) ChbC (CelC); IIA (106 aas) (Q72XQ1) |
|
4.A.3.2.9 | PTS-type lactose transporter, IIC-IIB-IIA (Imai and Hall 1981; Hall et al. 1982). | Bacteria |
Pseudomonadota | Lactose permease of Klebsiella pneumoniae |
|
4.A.3.2.10 | Oligo β-(gluco)mannoside (derived from (gluco)mannan))-specific PTS transporter, GmuABC (YdhNMO). The glucomannan utilization operon (gmuBACDREFG, formerly ydhMNOPQRST) of Bacillus subtilis has been characterized (Sadaie et al. 2008). Transcription of the operon is induced by konjac glucomannan and requires the last mannanase gene (gmuG). Cellobiose and mannobiose, possible degradation products of glucomannan by GmuG, are strong inducers of transcription. An internal regulatory gene (gmuR) encodes a repressor of the operon, as disruption of this gene enhances transcription of the operon in the absence of inducers. The expression of the glucomannan utilizing operon is thus induced by degraded glucomannan products, and repressed by an internal repressor (Sadaie et al. 2008). This system is induced by the presence of cellobiose in the growth medium (Chen et al. 2025). | Bacteria |
Bacillota | GmuABC of Bacillus subtilis GmuA, IIA, 110 aas, O05506 GmuB, IIB, 103 aas, O05505 GmuC, IIC, 422 aas and 10 TMSs, O05507 |
|
4.A.3.2.11 | Cellobiose PTS transporter with one IIC protein, CelC1, of 435 aas and 10 predicted TMSs(Q8Y3Z4, and two sets of IIAB proteins, CelA1 (100 aas; Q927F6) and CelB1 (101 aas; Q8Y3Z5) as well as CelA2 (100 aas; Q92AT9) and CelB2 (102 aas; Q8Y6G7). Another IIC-like protein was also found (454 aas; 10 TMSs; Q8Y3X1) but it did not phosphorlyate cellobiose, and its function was not identified. Transcription of these genes is regulated by CelR (Cao et al. 2019). UniProt acc#s for CelB1, CelA1 and CelC1 of E. faecalis are, respectively, Q836U0, Q836T9 and Q836T8. | Bacteria |
Bacillota | CelA1/A2/B1/B2/C1 of Listeria monocytogenes |
|
4.A.3.2.12 | PTS gentiobiose (glucosyl β-1,6-glucose) transporter, subunit IIC of 444 aas and 10 TMSs. May also transport several other beta-glucosides including inaribiose (β-1,3), chitobiose (NAcGlu-β-1,4), N(4)-β-Nacetyl-D-glucosaminyl-L-Asn (asparagine), chitobiose (NAG-β-1,4-NAG) and sophorose (β-1,2) (Combret et al. 2025). This PTS system is under the control of CelR, a LevR-like transcriptional activator (Combret et al. 2025). It uses IIA and IIB proteins from another PTS transporter, CelA1 and CelB1 (see TC# 4.A.3.2.13).
| None |
Bacillati, Bacillota | GenB (IICGen) of Enterococcus faecalis |
|
4.A.3.2.13 | Cellobiose PTS Enzyme IIC, IIA and IIB, Cel1C, Cel1A and Cel1B, respectively. Cel1C has 425 aas and 10 predicted TMSs (Combret et al. 2025). This system is the dominant cellobiose uptake system in E. faecalis. | None |
Bacillati | CelCAB of Enterococcus faecalis |
|
4.A.3.2.14 | PTS transporter, IICAB2cel. IIC has 487 aas and 10 predicted TMSs. This system transports cellobiose, cellotriose, and cellotetraose, and possible higher MW oligosaccharides in this series. It has its own IIB protein but uses the IIA protein of the Cel1 system (TC# 4.A.3.2.13) (Combret et al. 2025). In addition to IIC, IIA and IIB, three additional proteins seem to be required for function, although what these biochemical functions are is not known. These proteins are designated CelG (73 aas), CelH (67 aas) and CelI (137 aas) and are the last three proteins included in this system in TCDB (see Combret et al. 2025 for more details). UniProt acc #s for CelB2, CelC2, CelG, CelH and CelI of E. faecalis are Q836U5, Q836U4, Q836U3, Q836U2, and Q836U1, respectively. | None |
Bacillati, Bacillota | IICAB2Cel of Enterococcus faecalis |