Whole genome sequencing and functional gene screening of S-equol-producing Clostridium sp. C1

Abstract:

[Objective] This paper aims to investigate genes related to the production of S-equol from daidzein in Clostridium sp. C1, which is expected to serve as a reference for exploring the S-equol transformation mechanism in C1 and discover genes for the synthesis of S-equol by synthetic biology techniques.[Methods] Through the third-generation sequencing (GridION), assembly, and function annotation of the whole genome of C1, genes related to the biotransformation of S-equol were screened and identified.[Results] The genome was 3 035 113 bp, with 3 166 protein-coding genes, 53 tRNA genes, 15 rRNA genes, 4 ncRNA genes, and 1 genomic island. Bioinformatics analysis revealed that C1-07020 protein shared 44.8% amino acids and 3 conserved domains with daidzein reductase of Lactococcus sp. 20-92. In vitro verification showed that C1-07020 protein had similar functions to daidzein reductase. In addition, no other S-equol-producing gene clusters or other functional genes were identified from C1, which suggests that C1 may have a different metabolic mechanism from other S-equol-producing bacteria.[Conclusion] One S-equol-producing gene was identified from C1 and C1 might have a unique S-equol synthesis mechanism. The results of this study can serve as a reference for further exploring S-equol-producing genes, the production mechanism, and in vitro utilization of the genes.