RRC ID 22771
Author Watanabe S, Kakudo A, Ohta M, Mita K, Fujiyama K, Inumaru S.
Title Molecular cloning and characterization of the α-glucosidase II from Bombyx mori and Spodoptera frugiperda.
Journal Insect Biochem. Mol. Biol.
Abstract The α-glucosidase II (GII) is a heterodimer of α- and β-subunits and important for N-glycosylation processing and quality control of nascent glycoproteins. Although high concentration of α-glucosidase inhibitors from mulberry leaves accumulate in silkworms (Bombyx mori) by feeding, silkworm does not show any toxic symptom against these inhibitors and N-glycosylation of recombinant proteins is not affected. We, therefore, hypothesized that silkworm GII is not sensitive to the α-glucosidase inhibitors from mulberry leaves. However, the genes for B. mori GII subunits have not yet been identified, and the protein has not been characterized. Therefore, we isolated the B. mori GII α- and β-subunit genes and the GII α-subunit gene of Spodoptera frugiperda, which does not feed on mulberry leaves. We used a baculovirus expression system to produce the recombinant GII subunits and identified their enzyme characteristics. The recombinant GII α-subunits of B. mori and S. frugiperda hydrolyzed p-nitrophenyl α-d-glucopyranoside (pNP-αGlc) but were inactive toward N-glycan. Although the B. mori GII β-subunit was not required for the hydrolysis of pNP-αGlc, a B. mori GII complex of the α- and β-subunits was required for N-glycan cleavage. As hypothesized, the B. mori GII α-subunit protein was less sensitive to α-glucosidase inhibitors than was the S. frugiperda GII α-subunit protein. Our observations suggest that the low sensitivity of GII contributes to the ability of B. mori to evade the toxic effect of α-glucosidase inhibitors from mulberry leaves.
Volume 43(4)
Pages 319-27
Published 2013-4
DOI 10.1016/j.ibmb.2013.01.005
PII S0965-1748(13)00014-3
PMID 23376632
MeSH Animals Bombyx / chemistry Bombyx / enzymology* Bombyx / genetics Cloning, Molecular* Enzyme Stability Insect Proteins / chemistry* Insect Proteins / genetics* Insect Proteins / metabolism Spodoptera / chemistry Spodoptera / enzymology* Spodoptera / genetics Substrate Specificity alpha-Glucosidases / chemistry* alpha-Glucosidases / genetics* alpha-Glucosidases / metabolism
IF 3.618
Times Cited 2