Photoaffinity probe-enabled discovery of sennoside A reductase in Bifidobacterium pseudocatenulatum

Yang XU; Shujing LV; Xiang LI; Chuanjia ZHAI; Yulian SHI; Xuejiao LI; Zhiyang FENG; Gan LUO; Ying WANG; Xiaoyan GAO

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Photoaffinity probe-enabled discovery of sennoside A reductase in Bifidobacterium pseudocatenulatum

Author: Yang XU ¹ ; Shujing LV ¹ ; Xiang LI ¹ ; Chuanjia ZHAI ¹ ; Yulian SHI ¹ ; Xuejiao LI ¹ ; Zhiyang FENG ¹ ; Gan LUO ¹ ; Ying WANG ¹ ; Xiaoyan GAO ¹
Author Information

1. School of Chinese Materia Medica,Beijing University of Chinese Medicine,Beijing 102488,China
Publication Type:Journal Article
Keywords: Reductase; Sennoside A; Photoaffinity labeling; Gut bacteria; Transformation; Chemical biology; Small molecule
From: Journal of Pharmaceutical Analysis 2025;15(1):262-276
CountryChina
Language:English
Abstract: Sennoside A(SA),a typical prodrug,exerts its laxative effect only after its transformation into rhei-nanthrone catalyzed by gut microbial hydrolases and reductases.Hydrolases have been identified,but reductases remain unknown.By linking a photoreactive group to the SA scaffold,we synthesized a photoaffinity probe to covalently label SA reductases and identified SA reductases using activity-based protein profiling(ABPP).From lysates of an active strain,Bifidobacterium pseudocatenulatum(B.pseu-docatenulatum),397 proteins were enriched and subsequently identified using mass spectrometry(MS).Among these proteins,chromate reductase/nicotinamide adenine dinucleotide(NADH)phosphate(NADPH)-dependent flavin mononucleotide(FMN)reductase/oxygen-insensitive NADPH nitroreductase(nfrA)was identified as a potent SA reductase through further bioinformatic analysis and The Universal Protein Resource(UniProt)database screening.We also determined that recombinant nfrA could reduce SA.Our study contributes to further illuminating mechanisms of SA transformation to rheinanthrone and simultaneously offers an effective method to identify gut bacterial reductases.