4RYR: Crystal structure of BcTSPO, type 2 at 1.7 Angstrom with DMSO

Translocator proteins (TSPOs) bind steroids and porphyrins, and they are implicated in many human diseases, for which they serve as biomarkers and therapeutic targets. TSPOs have tryptophan-rich sequences that are highly conserved from bacteria to mammals. Here we report crystal structures for Bacillus cereus TSPO (BcTSPO) down to 1.7 A resolution, including a complex with the benzodiazepine-like inhibitor PK11195. We also describe BcTSPO-mediated protoporphyrin IX (PpIX) reactions, including catalytic degradation to a previously undescribed heme derivative. We used structure-inspired mutations to investigate reaction mechanisms, and we showed 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.
PDB ID: 4RYRDownload
MMDB ID: 126492
PDB Deposition Date: 2014/12/16
Updated in MMDB: 2018/07
Experimental Method:
x-ray diffraction
Resolution: 1.704  Å
Source Organism:
Similar Structures:
Biological Unit for 4RYR: monomeric; determined by author and by software (PISA)
Molecular Components in 4RYR
Label Count Molecule
Protein (1 molecule)
Integral Membrane Protein(Gene symbol: BC3136)
Molecule annotation
Chemicals (13 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB