Mutagenesis-induced conformational change in domain B of a pullulan-hydrolyzing α-amylase TVA I

Abstract: An α-amylase from Thermoactinomyces vulgaris, TVA I, hydrolyzes both α-1,4- and α-1,6-glucosidic linkages. Two variants of TVA I have been previously constructed, one containing a substitution of three residues, Ala357- Gln359-Tyr360, with Val-Asn-Glu (AQY/VNE), and the other bearing a deletion of 11 residues from Ala363 to Asn373 (Del11). The activities of both AQY/VNE and Del11 for the α-1,4-glucosidic linkage of maltotriose were decreased compared to that of wild-type TVA I, while the activities of the two variants for the α-1,6-glucosidic linkage of a trisaccharide, isopanose, were less significantly altered. Here, we determined the crystal structures of AQY/VNE and Del11. The structure of AQY/VNE was almost isomorphous with that of wild-type TVA I. On the other hand, the structure of Del11 showed that a conformational change in domain B was induced by the 11-residue deletion, causing narrowing of the catalytic cleft. Taken together with the results of kinetic analysis, this narrower catalytic cleft is likely responsible for the preference of the TVA I enzyme for the α-1,6-glucosidic linkage.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Mutagenesis-induced conformational change in domain B of a pullulan-hydrolyzing α-amylase TVA I ; volume:2 ; number:1 ; year:2018 ; pages:1-10 ; extent:10 ; Amylase ; 2, Heft 1 (2018), 1-10 (gesamt 10)

Contributors, Places and Time

• Creator: Tonozuka, Takashi ; Nihira, Takanori ; Mizuno, Masahiro ; Nishikawa, Atsushi ; Kamitori, Shigehiro

Further information

• DOI: 10.1515/amylase-2018-0001
• URN: urn:nbn:de:101:1-2404291539362.416864986263
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 14.08.2025, 10:55 AM CEST