Sulfur Amino Acids Biosynthetic Pathway in Pichia pastoris

Abstract:

Sulfur amino acids are essential for all living organisms. Pichia pastoris is a very important expression host in industrial fermentation，while its sulfur amino acids biosynthetic pathway is still unclear. To establish the pathway，bioinformatics approach and phenotypic analysis of mutants were employed in this study. Results indicated that Pichia pastoris synthesizes sulfur amino acids from inorganic sulfate via O-Acetyl-L-Homoserine and O-Acetyl-L-serine pathways. And methionine and cysteine can be inter-conversion by trans-sulfuration pathway. In addition，cys3Δ mutant showed selenomethionine resistance without supplementation of cysteine. Taken together，these results suggest a potential use of the cys3Δ strain for the production of selenomethionyl proteins.