1EHG

CRYSTAL STRUCTURES OF CYTOCHROME P450NOR AND ITS MUTANTS (SER286 VAL, THR) IN THE FERRIC RESTING STATE AT CRYOGENIC TEMPERATURE: A COMPARATIVE ANALYSIS WITH MONOOXYGENASE CYTOCHROME P450S

Summary for 1EHG

• Entry DOI: 10.2210/pdb1ehg/pdb
• Related: 1EHE 1EHF
• Descriptor: CYTOCHROME P450NOR, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: nitric oxide reductase, cytochrome p450nor, oxidoreductase
• Biological source: Fusarium oxysporum
• Total number of polymer chains: 1
• Total formula weight: 45049.23

Authors

Shimizu, H.,Park, S. (deposition date: 2000-02-21, release date: 2000-08-21, Last modification date: 2024-02-07)

Primary citation

Shimizu, H.,Park, S.,Lee, D.,Shoun, H.,Shiro, Y.
Crystal structures of cytochrome P450nor and its mutants (Ser286-->Val, Thr) in the ferric resting state at cryogenic temperature: a comparative analysis with monooxygenase cytochrome P450s.
J.Inorg.Biochem., 81:191-205, 2000

PubMed Abstract: Cytochrome P450nor (P450nor) is a heme enzyme isolated from the denitrifying fungus Fusarium oxysporum and catalyzes the NO reduction to N2O. Crystal structures of the wild type and two Ser286 mutants (Ser286-->Val, Ser286-->Thr) of P450nor have been determined for the ferric resting forms at a 1.7 A resolution at cryogenic temperature (100 K). We carried out three comparative analyses: (1) between the structures of P450nor at room temperature and cryogenic temperature, (2) between the structures of P450nor and four monooxygenase P450s, and (3) between the structures of the WT and the Ser286 mutant enzymes of P450nor. Comparison of the charge distribution on the protein surface suggests that proton and electron flow to the heme site is quite different in P450nor than in monooxygenase P450s. On the basis of the mutant structures, it was found that a special hydrogen-bonding network, Wat99-Ser286-Wat39-Asp393-solvent, acts as a proton delivery pathway in NO reduction by P450nor. In addition, the positively charged cluster located beneath the B'-helix is suggested as possible NADH binding site in P450nor, from which the direct two-electron transfer to the heme site allows to generate the characteristic intermediate in the NO reduction. These structural characteristics were not observed in structures of monooxygenase P450s, implying that these are factors determining the unique NO reduction activity of P450nor.

PubMed: 11051564
DOI: 10.1016/S0162-0134(00)00103-3

Experimental method

X-RAY DIFFRACTION (1.7 Å)