4RYJ: Crystal Structure Of Apo Dimer Of Bctspo

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: 4RYJDownload
MMDB ID: 126869
PDB Deposition Date: 2014/12/15
Updated in MMDB: 2015/02
Experimental Method:
x-ray diffraction
Resolution: 4.1  Å
Source Organism:
Similar Structures:
Biological Unit for 4RYJ: dimeric; determined by author and by software (PISA)
Molecular Components in 4RYJ
Label Count Molecule
Proteins (2 molecules)
Integral Membrane Protein(Gene symbol: BC3136)
Molecule annotation
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Citing MMDB