7LES
Acanthamoeba castellanii CYP51 (AcCYP51)-Imidazole complex
Summary for 7LES
| Entry DOI | 10.2210/pdb7les/pdb |
| Descriptor | Obtusifoliol 14alphademethylase, putative, PROTOPORPHYRIN IX CONTAINING FE, DI(HYDROXYETHYL)ETHER, ... (6 entities in total) |
| Functional Keywords | cyp51, ergosterol biosynthesis, acanthamoeba, 14-alpha-demethylase, oxidoreductase |
| Biological source | Acanthamoeba castellanii str. Neff |
| Total number of polymer chains | 4 |
| Total formula weight | 213306.38 |
| Authors | Sharma, V.,Podust, L.M. (deposition date: 2021-01-15, release date: 2021-12-22, Last modification date: 2023-10-18) |
| Primary citation | Nienhaus, K.,Sharma, V.,Nienhaus, G.U.,Podust, L.M. Homodimerization Counteracts the Detrimental Effect of Nitrogenous Heme Ligands on the Enzymatic Activity of Acanthamoeba castellanii CYP51. Biochemistry, 61:1363-1377, 2022 Cited by PubMed Abstract: is a free-living amoeba that can cause severe eye and brain infections in humans. At present, there is no uniformly effective treatment for any of these infections. However, sterol 14α-demethylases (CYP51s), heme-containing cytochrome P450 enzymes, are known to be validated drug targets in pathogenic fungi and protozoa. The catalytically active P450 form of CYP51 from (AcCYP51) is stabilized against conversion to the inactive P420 form by dimerization. In contrast, CYP51 (NfCYP51) is monomeric in its active P450 and inactive P420 forms. For these two CYP51 enzymes, we have investigated the interplay between the enzyme activity and oligomerization state using steady-state and time-resolved UV-visible absorption spectroscopy. In both enzymes, the P450 → P420 transition is favored under reducing conditions. The transition is accelerated at higher pH, which excludes a protonated thiol as the proximal ligand in P420. Displacement of the proximal thiolate ligand is also promoted by adding exogenous nitrogenous ligands (N-ligands) such as imidazole, isavuconazole, and clotrimazole that bind at the opposite, distal heme side. In AcCYP51, the P450 → P420 transition is faster in the monomer than in the dimer, indicating that the dimeric assembly is critical for stabilizing thiolate coordination to the heme and thus for sustaining AcCYP51 activity. The spectroscopic experiments were complemented with size-exclusion chromatography and X-ray crystallography studies. Collectively, our results indicate that effective inactivation of the AcCYP51 function by azole drugs is due to synergistic interference with AcCYP51 dimerization and promoting irreversible displacement of the proximal heme-thiolate ligand. PubMed: 35730528DOI: 10.1021/acs.biochem.2c00198 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.65 Å) |
Structure validation
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