Homology Modeling and Spectrophotometric Analysis of the Target Enzyme of DMI Fungicides CYP51 from Penicillium digitatum

Green mould, caused by Penicillium digitatum, is the most important post-harvest disease of citrus fruits in China. Sterol 14alpha-demethylase inhibitor (DMI) fungicides represent a kind of wildly used modern anti-fungal compounds. The decreasing sensitivity and field resistance to certain DMIs have been reported recently despite highly effective and specific single-site mode of action. In order to develop new DMI fungicides with more specific and stronger affinity, the 3D model of P. digitatum CYP51 (PdCYP51, ABC87815) was built based on structure template of 1e9x.pdb using FUGUE module of SYBYL7.0 program and the diniconazole was docked to the active site by FlexX. The binding model was reasonable. At the same time, spectral studies of diniconazole binding to purified P. digitatum CYP51 showed that diniconazole binding with the enzyme active center was effective also.