TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*2.C.1.1.1









The TonB energy-transducing system. ExbB/D are listed under TC# 1.A.30.2.1. The rotational surveillance and energy transfer (ROSET) model of TonB action postulates a mechanism for the transfer of energy from the Inner Membrane to the Outer Membrane, triggering iron uptake and concentration in the periplasm (Klebba 2016).

Bacteria
Proteobacteria
The TonB/ExbBD system of E. coli
*2.C.1.1.2









HasB (a distant TonB homologue that is specific for HasR (1.B.14.5.1)) (Benevides-Matos et al., 2008).
Bacteria
Proteobacteria
HasB of Serratia marcescens (Q79AD1)
*2.C.1.1.3









The CjrB TonB homologue of 258 aas;  involved in colicin J uptake together with CjrC, an outer membrane receptor (Smajs and Weinstock 2001).  CjrC has TC# 1.B.14.7.5.  They function together and are regulated by iron and temperature.

Bacteria
Proteobacteria
CjrB of E. coli
*2.C.1.1.4









TonB homologue of 244 aas and 1 TMS

Bacteria
Proteobacteria
TonB of Bdellovibrio bacteriovorus
*2.C.1.1.5









TonB-like protein of 195 aas

Bacteria
Proteobacteria
TonB-like protein of Bdellovibrio bacteriovorus
*2.C.1.1.6









TonB of 230 aas and 1 TMS

Bacteria
Acidobacteria
TonB of Acidobacterium capsulatum
*2.C.1.1.7









TonB of 248 aas and 1 TMS

Bacteria
Acidobacteria
TonB of Granulicella tundricola
*2.C.1.1.8









TonB of 359 aas and 1 N-terminal TMS

Bacteria
Acidobacteria
TonB of Acidobacterium capsulatum
*2.C.1.1.9









TonB of 250 aas and 1 TMS

Bacteria
Chlamydiae
TonB of Chlamydia psittaci
*2.C.1.1.10









TonB family protein of 272 aas and 1 N-terminal TMS.

Bacteria
Verrucomicrobia
TonB of Coraliomargarita sp. CAG:312
*2.C.1.1.11









Gram-negative bacterial TonB protein of 260 aas and 1 N-terminal TM

Bacteria
Planctomycetes
TonB of Candidatus Scalindua brodae
*2.C.1.2.1









The TolA energy-transducing system. The H+-channel-forming TolQ/R proteins are listed under TC# 1.A.30.2.2.  Proteins of the complex listed here are TolA, TolB, YbgF and Pal.  They play a role in outer membrane stabilization and uptake of colicins, but not energizaton of outer membrane receptors (OMRs: TC# 1.B.14).  May function in phospholipid transport (SS Chng, personal communication).  Cells lacking the Tol-Pal complex exhibit defects in lipid asymmetry and accumulate excess phospholipids (PLs) in the OM. This imbalance in OM lipids is due to defective retrograde PL transport in the absence of a functional Tol-Pal complex. Thus, cells ensure the assembly of a stable OM by maintaining an excess flux of PLs to the OM only to return the surplus to the inner membrane via transport mediated by the Tol-Pal complex (Shrivastava et al. 2017).  The specific function of the Tol-Pal complex may be to transport lipids from the outer leaflet of the outer membrane to the inner leaflet of the outer member. The Tol-Pal complex is essential to maintain polar localization of the MCP chemotaxis receptor complex (Santos et al. 2014). The Tol-Pal complex, energized by TolQRA, and using the outer membrane proteins, BtuB and OmpF as receptors, is responsible for the uptake of colicin ColE9 and other bacteriocins; in this process, the complex in the outer membrane bridges and immobilizes the complex components in the inner membrane (Rassam et al. 2018).

Bacteria
Proteobacteria
The TolA/TolQR/Pal system of E. coli
TolB (P0A855)
TolA (P19934)
YbgF (P45955)
Pal (C6EJJ6)
*2.C.1.2.2









Cell envelope energy-transducing integrity protein, TolA, of 421 aas. 

Bacteria
Proteobacteria
TolA of Pasteurella multocida
*2.C.1.2.3









TolA of 356 aas and 1 N-terminal TMS

Bacteria
Proteobacteria
TolA of Vibrio cholerae
*2.C.1.2.4









TolA of 371 aas

Bacteria
Proteobacteria
TolA of Gilliamella apicola
*2.C.1.3.1









TonB family protein, Slr1484, of 532 aas and 1 N-terminal TMS. Slr1484 had positive interactions with the three known ExbD proteins (Sll1405, Sll0479, and Slr0678) (Qiu et al. 2018).

Bacteria
Cyanobacteria
Slr1484 of Synechocystis 6803
*2.C.1.3.2









TonB family protein of 563 aas and 1 N-terminal TMS.

Bacteria
Cyanobacteria
TonB of Phormidium ambiguum
*2.C.1.3.3









TonB sfamily protein of 413 aas and 1 N-terminal TMS.

Bacteria
Cyanobacteria
Ton B of Aphanothece hegewaldii
*2.C.1.3.4









TonB family protein of 509 aas and 1 N-terminal TMS.

Bacteria
Cyanobacteria
TonB of Leptolyngbya foveolarum
*2.C.1.3.5









TonB of 410 aas and 1 N-terminal TMS.

Bacteria
Cyanobacteria
TonB of Rubidibacter lacunae
*2.C.1.3.6









TonB family protein of 512 aas and 1 N-terminla TMS. An uncharacterized constituent of a ferric siderophore transport system.

Bacteria
Cyanobacteria
TonB of Chrysosporum ovalisporum
*2.C.1.3.7









TonB energy transducer of 377 aas and 1 N-terminal TMS.

Bacteria
Proteobacteria
TonB of Acetobacter tropicalis
*2.C.1.3.8









TonB family protein of 372 aas and 1 TM

Bacteria
Planctomycetes
TonB of Pirellula staleyi
*2.C.1.4.1









TonB-like protein of 280 aas and 1 N-terminal TMS. It interacts with outer membrane receptor proteins that carry out high-affinity binding and energy-dependent uptake into the periplasmic space of specific substrates. It could act to transduce energy from the cytoplasmic membrane to specific energy-requiring processes in the outer membrane, resulting in the release into the periplasm of ligands bound by these outer membrane proteins.

Bacteria
Bacteroidetes
TonB of Bacteroides helcogenes
*2.C.1.4.2









TonB protein of 271 aas and 1 N-terminal TMS

Bacteria
Bacteroidetes
TonB of Bacteroides cellulosilyticus
*2.C.1.4.3









TonB protein of 320 aas and 1 TMS

Bacteria
Bacteroidetes
TonB of Bacteroides ovatus
*2.C.1.4.4









TonB of 272 aas and 1 TMS

Bacteria
Bacteroidetes
TonB of Flavobacterium psychrophilum