Characterization of the critical amino acids of an Aspergillus parasiticus Cytochrome P-450 monooxygenase encoded by ordA that is involved in the biosynthesis of aflatoxins B1, G1, B2, and G2

A study was conducted to clone the ordA and ordA1 genes of the aflatoxigenic strain Aspergillus parasiticus SRRC 143 and SRRC 2043, respectively, and to evaluate the function of the ordA gene in the formation of aflatoxins. Point mutations were introduced into the ordA gene using polymerase chain reaction-based site-directed mutagenesis while mycelia were obtained by filtration. Results indicated that cytochrome P-450 type enzymes were involved in the synthesis of different primary and secondary metabolites in filamentous fungi.