AUTHOR=Shi Xiaoyi , Geng Jiaran , Feng Jingxian , Yang Yingbo , Ma Xueqi , Chen Wansheng , Xiao Ying 

TITLE=Identification and investigation of a novel NADP+-dependent secoisolariciresinol dehydrogenase from Isatis indigotica

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1035121

DOI=10.3389/fpls.2022.1035121

ISSN=1664-462X

ABSTRACT=<p>Cofactors are crucial for the biosynthesis of natural compounds, and cofactor engineering is a useful strategy for enzyme optimization due to its potential to enhance enzyme efficiency. Secoisolariciresinol dehydrogenase (SIRD) was reported to convert secoisolariciresinol into matairesinol in an NAD<sup>+</sup>-dependent reaction. Here, a SIRD designated as <italic>Ii</italic>SIRD2 identified from <italic>Isatis indigotica</italic> was found to utilize NADP<sup>+</sup> as the cofactor. To explore the structural basis for this unique cofactor preference, model-based structural analysis was carried out, and it was postulated that a variation at the GXGGXG glycine-rich motif of <italic>Ii</italic>SIRD2 alters its cofactor preference. This study paves way for future investigations on SIRD cofactor specificity and cofactor engineering to improve SIRD’s catalytic efficiency.</p>