Deciphering the Crucial Roles of the Quorum-Sensing Transcription Factor SdiA in NADPH Metabolism and (<i>S</i>)-Equol Production in <i>Escherichia coli</i> Nissle 1917

• Main Authors: Zhe Wang (Author), Yiqiang Dai (Author), Fidelis Azi (Author), Mingsheng Dong (Author), Xiudong Xia (Author)
• Format: Book
• Published: MDPI AG, 2024-02-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

The active metabolite (<i>S</i>)-equol, derived from daidzein by gut microbiota, exhibits superior antioxidative activity compared with its precursor and plays a vital role in human health. As only 25% to 50% of individuals can naturally produce equol when supplied with isoflavone, we engineered probiotic <i>E. coli</i> Nissle 1917 (EcN) to convert dietary isoflavones into (<i>S</i>)-equol, thus offering a strategy to mimic the gut phenotype of natural (<i>S</i>)-equol producers. However, co-fermentation of EcN-eq with fecal bacteria revealed that gut microbial metabolites decreased NADPH levels, hindering (<i>S</i>)-equol production. Transcriptome analysis showed that the quorum-sensing (QS) transcription factor SdiA negatively regulates NADPH levels and (<i>S</i>)-equol biosynthesis in EcN-eq. Screening AHLs showed that SdiA binding to C10-HSL negatively regulates the pentose phosphate pathway, reducing intracellular NADPH levels in EcN-eq. Molecular docking and dynamics simulations investigated the structural disparities in complexes formed by C10-HSL with SdiA from EcN or <i>E. coli</i> K12. Substituting <i>sdiA_EcN</i> in EcN-eq with <i>sdiA_K12</i> increased the intracellular NADPH/NADP⁺ ratio, enhancing (<i>S</i>)-equol production by 47%. These findings elucidate the impact of AHL-QS in the gut microbiota on EcN NADPH metabolism, offering insights for developing (<i>S</i>)-equol-producing EcN probiotics tailored to the gut environment.

Item Description

10.3390/antiox13030259
2076-3921