Role of Glu720 mutation in transglycosylating α-glucosidase derived from Aspergillus neoniger NCIM 1400

Trisha, Tissopi and Dhruv, Mistry and Ritesh, Ranjan and Rakshit, Upreti and Sandeep, Kumar and Mukesh, Kapoor and Sarma, Mutturi (2025) Role of Glu720 mutation in transglycosylating α-glucosidase derived from Aspergillus neoniger NCIM 1400. International Journal of Biological Macromolecules, 319. pp. 1-16.

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Abstract

Transglycosylating α-glucosidase (tAG) is used as processing aid for the industrial production of iso- maltooligosaccharides (IMO). Glutamate residue at 720 position (E720) was rationally selected and mutated to elucidate its role in the catalytic activity (hydrolytic and transglycosylation) and conformational changes of the enzyme. Seven mutant libraries of the wtAG (wild-type tAG) were successfully constructed, and amongst them, E720Y showed a 1.9-fold increase in the specific hydrolytic activity over the wtAG. The thermostability of E720Y was 11 % higher than that of wtAG. The E720Y mutation significantly prolonged storage stability over a 45-day period with 71.6 % and 63 % of its relative activity at 4 ◦C and 30 ◦C, respectively, whereas wtAG retained only 46.3 % and 33.6 % of its relative activity at those temperatures. Circular dichroism (CD) and steady-state fluorescence studies suggested that E720Y mutation had a subtle effect on the secondary structure (reduced random coil and higher α-helical content) but led to no major changes in the tertiary structure of wtAG. The Molecular dynamics simulation results indicate that E720Y induces structural changes, which align with the findings from the CD analysis. The total IMO yield of wtAG and E720Y mutant was found to be 0.29 and 0.38 g g 1 of maltose, respectively.

Item Type:	Article
Uncontrolled Keywords:	Transglycosylating α-glucosidase, Site-directed mutagenesis, Circular dichroism, aspergillus neoniger
Subjects:	600 Technology > 08 Food technology > 16 Nutritive value > 05 Enzymes 600 Technology > 08 Food technology > 29 Microbiological food > 02 Fungi
Divisions:	Food Microbiology
Depositing User:	Somashekar K S
Date Deposited:	07 Oct 2025 06:54
Last Modified:	07 Oct 2025 06:54
URI:	http://ir.cftri.res.in/id/eprint/19905

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