1LKD: Crystal Structure Of 2,3-Dihydroxybiphenyl 1,2-Dioxygenase (Dhbd) Complexed With 2',6'-Dicl Dihydroxybiphenyl (Dhb)

The microbial degradation of polychlorinated biphenyls (PCBs) provides the potential to destroy these widespread, toxic and persistent environmental pollutants. For example, the four-step upper bph pathway transforms some of the more than 100 different PCBs found in commercial mixtures and is being engineered for more effective PCB degradation. In the critical third step of this pathway, 2,3-dihydroxybiphenyl (DHB) 1,2-dioxygenase (DHBD; EC catalyzes aromatic ring cleavage. Here we demonstrate that ortho-chlorinated PCB metabolites strongly inhibit DHBD, promote its suicide inactivation and interfere with the degradation of other compounds. For example, k(cat)(app) for 2',6'-diCl DHB was reduced by a factor of approximately 7,000 relative to DHB, and it bound with sufficient affinity to competitively inhibit DHB cleavage at nanomolar concentrations. Crystal structures of two complexes of DHBD with ortho-chlorinated metabolites at 1.7 A resolution reveal an explanation for these phenomena, which have important implications for bioremediation strategies.
PDB ID: 1LKDDownload
MMDB ID: 21161
PDB Deposition Date: 2002/4/24
Updated in MMDB: 2002/12
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 1LKD: octameric; determined by author and by software (PISA,PQS)
Molecular Components in 1LKD
Label Count Molecule
Proteins (8 molecules)
Biphenyl-2,3-diol 1,2-dioxygenase(Gene symbol: bphC)
Molecule annotation
Chemicals (40 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB