朱砂精酸生物合成体系的构建和应用

Construction and application of the cinnabarinic acid biosynthetic system

摘要:

朱砂精酸(cinnabarinic acid, CA)是一种广泛用于印染、化工和制药等行业的高值含氮三杂环吩恶嗪酮类化合物，但至今尚未建立有效的CA合成体系。为实现CA的高效合成，本研究构建了基于体外酶学催化和全细胞催化的CA生物合成体系。首先，针对CA合成的关键限制因素，筛选到了一个可加速将3-羟基邻氨基苯甲酸转化为CA的超氧化物歧化酶SodA_Prm。随后，通过对SodA_Prm催化条件的优化，于体外实现了高达(176.6±14.3) mg/L的CA合成。此后，基于SodA_Prm酶，构建了用于CA合成的全细胞催化体系BL-sodA_Prm。最后，通过对全细胞催化系统BL-sodA_Prm催化条件的优化，最终实现了高达312.3 mg/L的CA合成。本研究为未来CA及其衍生物的高效合成与应用奠定了研究基础。

Abstract:

Cinnabarinic acid (CA) is a high-value nitrogen-containing tricyclic phenoxazinone widely used in dyeing, chemical, and pharmaceutical industries. However, the efficient CA synthetic system for large-scale CA production has not been constructed until now. To achieve efficient CA biosynthesis, we constructed an in vitro enzymatic synthetic system and a whole-cell biocatalytic platform for CA biosynthesis in this study. Firstly, targeting the main limiting factor of the CA synthesis, we identified a superoxide dismutase SodA_Prm capable of efficiently converting 3-hydroxyanthranilate to CA. Subsequently, the in vitro catalytic parameters of SodA_Prm were optimized, after which (176.6±14.3) mg/L CA was efficiently synthesized. Then, based on the selected SodA_Prm, an Escherichia coli whole-cell catalytic system BL-sodA_Prmwas constructed for CA biosynthesis. Finally, a maximal titer of 312.3 mg/L CA was synthesized after optimization of the reaction conditions of whole-cell catalytic system BL-sodA_Prm. In summary, this study lays a profoundly foundation for the biosynthesis and application of CA and its derivatives in the future.