Constructing Protein-Scaffolded Multienzyme Assembly Enhances the Coupling Efficiency of the P450 System for Efficient Daidzein Biosynthesis from (2S)-Naringenin

Daidzein is a major isoflavone compound with an immense pharmaceutical value. This study applied a novel P450 CYP82D26 which can biosynthesize daidzein from (2S)-naringenin. However, the recombinant P450 systems often suffer from low coupling efficiency, leading to an electron transfer efficiency decrease and harmful reactive oxygen species release, thereby compromising their stability and catalytic efficiency. To address these challenges, the SH3-GBD-PDZ (SGP) protein scaffold was applied to assemble a multienzyme system comprising CYP82D26, P450 reductase, and NADP+-dependent aldehyde reductase in desired stoichiometric ratios. Results showed that the coupling efficiency of the P450 system was significantly increased, primarily attributed to the channeling effect of NADPH resulting from the proximity of tethered enzymes and the electrostatic interactions between NADPH and SGP. Assembling this SGP-scaffolded assembly system in Escherichia coli yielded a titer of 240.5 mg/L daidzein with an 86% (2S)-naringenin conversion rate, which showed a 9-fold increase over the free enzymes of the P450 system. These results underscore the potential application of the SGP-scaffolded multienzyme system in enhancing the coupling and catalytic efficiency of the P450 system.