[P001] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P01-087] Discovery of a novel methionine biosynthetic route in Streptomyces

○Fumihito Hasebe¹, Chitose Maruyama¹, Yoshimitsu Hamano¹ (1. Fukui Prefectural University (Japan))

Keywords:

methionine biosynthesis,Streptomyces,sulfur carrier protein,homocysteine synthase

Methionine (Met), a sulfur-containing amino acid, is essential for the underlying biological processes in living organisms. In addition to its importance as a starting building block for peptide chain elongation in protein biosynthesis, Met is a direct precursor of S-adenosyl-L-methionine, an indispensable methyl donor molecule in primary and secondary metabolism. Streptomyces bacteria are well known to produce diverse secondary metabolites, but many strains lack canonical Met pathway genes for L-homocysteine, a direct precursor of Met in bacteria, plants, and archaea. Here, we report the identification of the unprecedented gene (metM) responsible for the Met biosynthesis in the Streptomyces strains and demonstrate the catalytic function of the gene product, MetM^[1]. We further identified the metO gene, a downstream gene of metM, encodes a sulfur carrier protein. In vitro analysis using their recombinant enzymes, MetO was found to play an important role in a sulfur donor by forming a thiocarboxylated MetO. Moreover, MetM converted O-phospho-L-homoserine to l-homocysteine using the thiocarboxylated MetO as a sulfur donor. Based on the BLAST analysis, metM homolog genes are highly conserved in Streptomyces bacteria and distributed in some Archaea (e.g., Euryarchaeota and Thaumarchaeota) and Bacteria (e.g., Actinomycetota, Cyanobacteria, Acidobacteriota, Nitrospirota, and Aquificota).

Reference
[1]. Hasebe, F., Adachi, K., Maruyama, C., Hamano, Y. (2024). Appl. Environ. Microbiol. 90.(10.): e0124724.