TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*9.A.24.1.1









The peripheral benzodiazepine receptor (PBR), which can also bind isoquinoline carboxamides (Riond et al. 1991) and integrates into the mitochondrial outer membrane (MOM) through five hydrophobic transmembrane segments (TMSs). Also called "translocator protein", TSPO). It is a mitochondrial cholesterol and porphyrin uptake transporter (Jaremko et al. 2014; Taylor et al. 2014) but is also part of the mitochondrial permeability transition pore (MPTP) which includes cyclophilin D, VDAC (TC#1.B.8) and the adenine nucleotide translocator (Austin et al. 2013).  The 3-d structure has been determined at 2.4 Å resolution bound to its high affinity ligand, PK11195 which causes the otherwise loose 5 helix bundle to form a tight bundle with a hydrophobic pocket for PK11195 (Jaremko et al. 2014).

Eukaryota
Metazoa
PBR of Homo sapiens (Q6ICF9)
*9.A.24.1.2









The outer membrane tryptophan-rich sensory protein (TspO) of the TSPO/MBR family of 159 aas and 5 TMSs (Yeliseev et al. 1997; Yeliseev and Kaplan 1999).  The 10 Å cryo electron microscopy structure is known (Korkhov et al. 2010) as are 1.8, 2.4 and 2.5 Å structures solved by x-ray crystallography (Li et al. 2015).  Crystals obtained in the lipidic cubic phase reveal the binding site of an endogenous porphyrin ligand. The three crystal structures reveal a dimer, providing insights into the controversial physiological role of TSPO and how a mutation in the human homologue causes psychiatric disorders and reduced pregnenolone production (Li et al. 2015).

Bacteria
Proteobacteria
TspO of Rhodobacter spheroides
*9.A.24.1.3









The Endoplasmic reticulum/Golgi TSPO protein is mainly detected in dry seeds, but can be induced in vegetative tissues by osmotic or salt stress or abscisic acid (ABA) treatment (Guillaumot et al. 2009).

Eukaryota
Viridiplantae
TSPO of Arabidopsis thaliana
*9.A.24.1.4









Bacteria
Cyanobacteria
TspO of Nostoc sp.
*9.A.24.1.5









TspO/MBR family protein of 186 aas and 5 TMSs
Eukaryota
Longamoebia
TspO/MBR family protein of Acanthamoeba castellanii
*9.A.24.1.6









Bacteria
Bacteroidetes/Chlorobi group
TspO of Niastella koreensis
*9.A.24.1.7









TspO of 159 aas

Bacteria
Firmicutes
TspO of Lactococcus lactis
*9.A.24.1.8









Peripheral-type benzodiazepine receptor of 188 aas
Eukaryota
Viridiplantae
Peripheral-type benzodiazepine receptor of Zea mays
*9.A.24.1.9









TspO homologue of 193 aas

Eukaryota
Viridiplantae
TspO of Oryza sativa
*9.A.24.1.10









Uncharacterized protein of 171 aas and 5 TMSs

Eukaryota
Metazoa
UP of Loa loa (Eye worm) (Filaria loa)
*9.A.24.1.11









TspO protein of 141 aas and 4-5 TMSs

Viruses
Phycodnaviridae
TspO of Phaeocystis globosa virus
*9.A.24.1.12









TspO-like; MBR-like protein of 163 aas

Eukaryota
Bangiophyceae
TspO-like protein of Galdieria sulfuraria
*9.A.24.1.13









TspO/MBR family member of 151 aas and 5 TMSs.  The crystal structure has been determined at 1.7 Å resolution (Guo et al. 2015).  The protein was solved in complex with the benzodiazepine-like inhibitor, PK11195. TspO-mediated protoporphyrin IX (PpIX) reactions were also described, including catalytic degradation to a previously undescribed heme derivative. Structure-inspired mutations allowed the investigation of the reaction mechanisms, showing that TSPOs from Xenopus and man have similar PpIX-directed activities. Although TSPOs have been regarded as transporters, the catalytic activity in PpIX degradation suggests physiological importance for TSPOs in protection against oxidative stress (Guo et al. 2015).

Bacteria
Firmicutes
TspO of Bacillus cereus
*9.A.24.1.14









Uncharacterized protein of 134 aas and 4 TMSs (Hug et al. 2016).

Bacteria
Candidatus Peregrinibacteria
UP of Candidatus Peribacter riflensis
*9.A.24.1.15









Uncharacterized protein of 161 aas and 4 TMSs.

Bacteria
Proteobacteria
UP of Luteimonas mephitis
*9.A.24.1.16









Tryptophan-rich sensory protein. TSPO, of 167 aas and 5 TMSs

Archaea
Euryarchaeota
TSPO of Halococcus sediminicola
*9.A.24.2.1









TspO homologue of 171 aas

Bacteria
Proteobacteria
TspO homologue of Maricaulis maris
*9.A.24.2.2









CrtK protein of 166 aas and 5 TMSs.

Bacteria
Proteobacteria
CrtK of Oceanicaulis sp.
*9.A.24.3.1









Uncharacterized protein of 177 aas

Bacteria
Actinobacteria
UP of Mycobacterium vanbaalenii
*9.A.24.3.2









Tryptophan-rich sensory proteinof 160 aas and 5 TM

Bacteria
Actinobacteria
TpsO of Nocardia soli
*9.A.24.4.1









Uncharacterized protein, WcoO of 272 aas and 8 TMSs.

Bacteria
Actinobacteria
WcoO of Clavibacter michiganensis
*9.A.24.4.2









Uncharacterized protein of 258 aas

Bacteria
Firmicutes
UP of Bacillus selenitireducens
*9.A.24.4.3









Uncharacterized protein of 290 aas and 8 TMSs

Bacteria
Actinobacteria
UP of Coriobacterium glomerans
*9.A.24.4.4









Uncharacterized protein of 281 aas and 8 TMSs.

Eukaryota
Peronosporales
UP of Phytophthora infestans (Potato late blight fungus)
*9.A.24.4.5









Uncharacterized protein of 264 aas and 8 TMSs.

Eukaryota
Fungi
UP of Rhizophagus irregularis (Arbuscular mycorrhizal fungus) (Glomus intraradices)
*9.A.24.4.6









Uncharacterized protein of 350 aas and 8 TMSs.

Eukaryota
Cryptophyta
UP of Guillardia theta
*9.A.24.4.7









Uncharacterized protein of 277 aas and 7 TMSs

Bacteria
Actinobacteria
UP of Microbacterium yannicii
*9.A.24.4.8









Uncharacterized protein of 236 aas and 8 TMSs.

Bacteria
Proteobacteria
UP of Paracoccus zeaxanthinifaciens
*9.A.24.4.9









Uncharacterized protein of 250 aas and 8 TMSs.

Bacteria
Proteobacteria
UP of Henriciella aquimarina
*9.A.24.4.10









Uncharacterized protein of 155 aas and 5 TMSs.

Archaea
Euryarchaeota
UP of Methanosarcina mazei