Cloning and Expression of the Cytochrome P-450nor2 cDNA from Cylindrocarpon tonkinense.

Cytochrome P-450nor is involved in the fungal denitrification and acts as a nitric oxide reductase. The cDNA library from Cylindrocarpon tonkinense was constructed with lambdagtll, and screened with antibodies. From the positive clones, the P-450nor2 cDNA fragments were recovered, and subcloned into the expression vector pYES2, then expressed in the yeast system. Western blot analysis showed that the expressed protein was hybridized with the antibody. Enzyme assay indicated that the expressed protein had the activities of P-450nor2, which reduced NO to form N(2)O, employing NADH or NADPH as the sole electron donor.