Sake yeast YHR032W/ERC1 haplotype contributes to high S-adenosylmethionine accumulation in sake yeast strains

摘要

kanai@nrib.go.jp;;;;;;;;;;;; and producing greater levels of various aromatic components and nutrients than laboratory yeasts. To elucidate the mechanism underlying 5-adenosylmethionine (SAM) accumulation in sake yeast strains compared with that in labo- VIII. Of the 165 genes mapped at 49.8 cM from the left-end DNA marker of chromosome VIII, we focused on the YHR032W/ERC1 gene, encoding a member of the multi-drug and toxin extrusion family having antiporter activity and involved in SAM accumulation and ethionine resistance. Expression of the sake yeast ERC1 haplotype (K7ERC1) in a low-and high-copy number piasmid BY △erc1 resulted in intracellular SAM accumulation, whereas expression of the laboratory yeast ERC1 haplotype (XERC1)did not Comparison between DNA sequences of K7ERC1 and XERC1 revealed three amino acid substitutions: S51N, V263I, and N545I. Site-directed mutagenesis revealed that the N545I frameshift muta- sake yeast strains.