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

    2 Citations (Scopus)

    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

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

    ASJC Scopus subject areas

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

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