Cloning, expression and functional identification of cytochrome P450 reductase gene in Aquilaria sinensis / 药学学报

ABSTRACT

Cytochrome P450 reductase (CPR) is essential for the electron transport chain of cytochrome P450s, playing an indispensable role in electron transfer in vivo. In this study, one cDNA encoding cytochrome P450 reductase (Ascpr1) was identified from the callus of Aquilaria sinensis. Ascpr1 contains an open reading frame of 2 124 bp. The deduced protein is composed of 707 amino acids, with a predicted molecular weight of 78.82 kD. Phylogenetic analysis revealed that AsCPR1 is a type Ⅱ CPR protein closely related to the CPR from Theobroma cacao. Transmembrane prediction using TMHMM 2.0 indicated that the amino acids 52-71 of AsCPR1 comprise a transmembrane region. After truncating of 67 amino acid residues from N-terminal, the truncated AsCPR1 was successfully expressed in E. coli Transetta (DE3). Further purification of the recombinant AsCPR1 by affinity chromatography and determination of the enzymatic activity allowed the reducing ability of AsCPR1 to cytochrome C in vitro. The results pave the way for further study on the synthesis of defensive chemicals involved in P450s and the functions of CPR in self-defense of A. sinensis.