Modification of the transglucosylation properties of α-glucosidases from Aspergillus oryzae and Aspergillus sojae via a single critical amino acid replacement

Abstract

We constructed enzyme variants of the α-glucosidases from Aspergillus oryzae (AoryAgdS) and Aspergillus sojae (AsojAgdL) by mutating the amino acid residue at position 450. AoryAgdS_H450R acquired the ability to produce considerable amounts of α-1,6-transglucosylation products, whereas AsojAgdL_R450H changed to produce more α-1,3- and α-1,4-transglucosylation products than α-1,6-products. The 450th amino acid residue is critical for the transglucosylation of these α-glucosidases.

Manipulation of an α-glucosidase in the industrial glucoamylase-producing Aspergillus niger strain O1 to decrease non-fermentable sugars production and increase glucoamylase activity

“…The residues 457–560 of Aspergillus sojae ( A. sojae ) were found to be the structural basis of transglycosylation activity, corresponding to the middle part of Glyco_hydro_31 domain in agdB ( Ding et al, 2022 ). Mutation of the amino acid residue H450 or R450 in α-glucosidases from A. oryzae and A. sojae changed the types and amounts of transglycosylation products ( Kawano et al, 2021 ). Similarly, mutation of N696 in A. niger α-glucosidase modified transglycosylation properties ( Ma et al, 2017 ).…”

“…The intracellular α-glucosidase MalT in A. oryzae can convert maltose to isomaltose by transglycosylation, thereby controlling the activation of the transcription factor amyR that is essential for amylolytic gene expression (Ichikawa et al, 2021). α-Glucosidases play important roles in fermentation and have been used to achieve desirable tastes in miso by producing large amounts of isomaltooligosaccharides (Kawano et al, 2021).…”

“…The intracellular α-glucosidase MalT in A. oryzae can convert maltose to isomaltose by transglycosylation, thereby controlling the activation of the transcription factor amyR that is essential for amylolytic gene expression ( Ichikawa et al, 2021 ). α-Glucosidases play important roles in fermentation and have been used to achieve desirable tastes in miso by producing large amounts of isomaltooligosaccharides ( Kawano et al, 2021 ). The transglycosylation activity of α-glucosidases allows them to produce a variety of oligosaccharides, such as isomaltooligosaccharides (α-1, 6-glucooligosaccharides), nigerooligosaccharides (α-1, 3-glucooligosaccharides), and kojibiose (α-1, 2-glucobiose) ( Ma et al, 2019 ).…”