[Cloning and functional characterization of the pinoresinol-lariciresinol reductase gene in ].

The pinoresinol-lariciresinol reductase (PLR), a crucial enzyme in the biosynthesis of lignans in plants, catalyzes a two-step reaction to produce lariciresinol and secoisolariciresinol. Lignans such as lariciresinol are the effective components of traditional Chinese medicine Radix Isatidis in exerting antiviral activity. In order to study the function of the key enzyme PLR in the biosynthesis of lariciresinol in , the original plant of Radix Isatidis, was cloned from , with a full length of 954 bp, encoding 317 amino acids. Multiple sequence alignment showed that PLR2 contained a conserved nicotinamide adenine dinucleotide phosphate (NADPH)-binding motif. The phylogenetic tree showcased that PLR2 shared the same clade with PrR1 from . The prokaryotic expression vector pET32a-PLR2 was constructed and then transformed into BL21(DE3) competent cells for protein expression. The purified enzyme PLR2 could catalyze the conversion of pinoresinol to lariciresinol and the conversion of lariciresinol to secoisolariciresinol. The cloning, sequencing, and catalytic functional analysis of PLR2 in this study enrich the understanding of this kind of functional proteins in . and supplement the biosynthesis pathways of lignans. Moreover, this study provides a functional module for further research on metabolic regulation and synthetic biology and lays a foundation for comprehensively revealing the relationship between the spatial structures and catalytic functions of such proteins.