TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*5.B.5.1.1









The multihaem c-type cytochrome quinol:Fe3+ /Mn3 /4+ oxidoreductase, Cym/Mtr (Shi et al., 2007).  MtrABC is composed of two decahaem cytochromes brought together inside a transmembrane porin to transport electrons across the outer membrane to mineral based electron acceptors (White et al. 2012).  Conduction through MtrCAB directly to Fe(III) oxides occurs both in vitro in liposomes and in vivo, allowing anaerobic, solid-phase iron respiration (White et al. 2013). MtrC interacts with the surface of MtrAB, extending ∼70 Å from the membrane surface and allowing the terminal hemes to interact with both MtrAB and an extracellular acceptor. MtrA fully extends through the length of MtrB, with ∼30 Å being exposed into the periplasm. MtrCAB can reduce Fe(III) citrate with STC as an electron donor, disclosing a direct interaction between MtrCAB and STC (Edwards et al. 2018).

Bacteria
Proteobacteria
Cym/Mtr of Shewanella oneidensis
CymA (quinol dehydrogenase; 187 aas)
(~34% identical to TorY; TC# 5.A.3.4.2)
(Q8E8S0)
MtrA (decaheme cytochrome c; 330 aas)
(21% identical to the polyheme membrane associated cytochrome c; TC# 5.B.3.1.1)
(Q8EG35)
MtrB (outer membrane protein precursor with homology to parts of members of the AT family, TC# 1.B.12; 697 aas)
(similar to PioB of the phototrophic iron (Fe2+)
oxidoreductase oxidizing (Pio), CO2 reducing complex of
Rhodopseudomonas palustris; TC# 5.B.5.2.1))
MtrC dodecaheme cytochrome c; 671 aas
(Q8EG34)
OmcA (decaheme cytochrome c; 735 aas;
may be distantly related to cyt c3 of Geobacter sulfurreducens; TC# 5.B.3.1.1)
(Q8EG33)
*5.B.5.1.2









Four component transenvelope ferrous oxidase, CymA/MtoA/MtoB/MtoD (Beckwith et al. 2015). 

Bacteria
Proteobacteria
Ferrous oxidase of Sideroxydans lithotrophicus
*5.B.5.1.3









Extracellular respiratory system surface decaheme cytochrome c component MtrF of 639 aas.

Bacteria
Proteobacteria
MtrF of Shewanella oneidensis
*5.B.5.1.4









Surface localized decaheme cytochrome c lipoprotein of 759 aas.

Bacteria
Proteobacteria
Lipoprotein of Shewanella oneidensis
*5.B.5.2.1









The secreted phototrophic iron (Fe2+) oxidase (CO2 reducing); PioABC (Jiao and Newman, 2007)
Bacteria
Proteobacteria
PioABC of Rhodopseudomonas palustris
PioA (c-type cytochrome; like MtrA)
(A1EBT2)
PioB (outer membrane β-barrel protein; like MtrB)
(A1EBT3)
PioC (high potential iron sulfer protein, HiPIP similar to the Fe2+ oxidoreducatse (Iro) of Acidithiobacillus ferrooxidans)
(A1EBT4)