Mechanistic Insight into Biotransformation of Inorganic Selenium to Selenomethionine and Selenocysteine by Saccharomyces boulardii: In-silico Study

Abstract

In recent years, the biosynthesis of seleno amino acids from inorganic selenium has been a subject of investigation. Saccharomyces cerevisiae has been reported to bioaccumulate selenium through the metabolism of selenate. Different authors have postulated a metabolic pathway in which selenate is converted into selenomethionine or selenocysteine based on the research carried out so far. However, little has been known how other types of yeast achieve this bioconversion. For that reason, and due to the importance of Saccharomyces boulardii as a probiotic yeast, the present study proposes a biosynthetic route used by this yeast to incorporate inorganic selenium into organoselenium compounds. A comparative in-silico study was carried out using Saccharomyces boulardii ASM141397V1 and a metabolic model at the genomic scale of Saccharomyces cerevisiae S288C. Basic local alignment database BLASTp-NCBI was used to identify orthologous genes in both strains, and the generated data were visualized in a circular layout using CIRCOS software. The metabolic route of selenium assimilation was proposed based on the obtained results.