Crucial role of the intracellular α-glucosidase MalT in the activation of the transcription factor AmyR essential for amylolytic gene expression in Aspergillus oryzae

Takanori Ichikawa, Mizuki Tanaka, Takayasu Watanabe, Sitong Zhan, Akira Watanabe, Takahiro Shintani, Katsuya Gomi

Research output: Contribution to journalArticlepeer-review

Abstract

We examined the role of the intracellular α-glucosidase gene malT, which is part of the maltose-utilizing cluster (MAL cluster) together with malR and malP, in amylolytic gene expression in Aspergillus oryzae. malT disruption severely affected fungal growth on medium containing maltose or starch. Furthermore, the transcription level of the α-amylase gene was significantly reduced by malT disruption. Given that the transcription factor AmyR responsible for amylolytic gene expression is activated by isomaltose converted from maltose incorporated into the cells, MalT may have transglycosylation activity that converts maltose to isomaltose. Indeed, transglycosylated products such as isomaltose/maltotriose and panose were generated from the substrate maltose by MalT purified from a malT-overexpressing strain. The results of this study, taken together, suggests that MalT plays a pivotal role in AmyR activation via its transglycosylation activity that converts maltose to the physiological inducer isomaltose.

Original languageEnglish
Pages (from-to)2076-2083
Number of pages8
JournalBioscience, Biotechnology and Biochemistry
Volume85
Issue number9
DOIs
Publication statusPublished - 2021 Sep 1

Keywords

  • amylolytic gene expression
  • AmyR activation
  • Aspergillus oryzae
  • intracellular α-glucosidase MalT
  • transglycosylation

ASJC Scopus subject areas

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

Fingerprint

Dive into the research topics of 'Crucial role of the intracellular α-glucosidase MalT in the activation of the transcription factor AmyR essential for amylolytic gene expression in Aspergillus oryzae'. Together they form a unique fingerprint.

Cite this