Asp578 in LEU4p is one of the key residues for leucine feedback inhibition release in sake yeast

Takahiro Oba, Shuji Nomiyama, Hideki Hirakawa, Kosuke Tashiro, Satoru Kuhara

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


We identified a new mutation, Asp578Tyr, in α-isopropylmalate synthase (a LEU4 gene product) that releases leucine feedback inhibition and causes hyperproduction of isoamyl alcohol (i-AmOH) in sake yeast. Spontaneous sake yeast mutants that express resistance to 5,5,5-trifluoro-DL-leucine (TFL) were isolated, and a mutant strain, TFL20, was characterized at the genetic and biochemical levels. An enzyme assay for α-isopropylmalate synthase showed that strain TFL20 was released from feedback inhibition by L-leucine. Furthermore, DNA sequencing of the LEU4 gene for a haploid of the mutant TFL20 revealed that aspartic acid in position 578 changes to tyrosine. A comparison of the three-dimensional structures of wild-type LEU4p and mutant LEU4D578Yp by the homology modeling method showed that Asp578 is important for leucine feedback inhibition. We conclude that the mutation from Asp to Tyr in 578 is a novel change causing release from leucine feedback inhibition.

Original languageEnglish
Pages (from-to)1270-1273
Number of pages4
JournalBioscience, Biotechnology and Biochemistry
Issue number7
Publication statusPublished - 2005

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Analytical Chemistry
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology
  • Organic Chemistry


Dive into the research topics of 'Asp578 in LEU4p is one of the key residues for leucine feedback inhibition release in sake yeast'. Together they form a unique fingerprint.

Cite this