title: Characterization and gene cloning of a maltotriose-forming exo-amylase from Kitasatospora sp. MK-1785.
abstract: A maltotriose-forming amylase (G3Amy) from Kitasatospora sp. MK-1785 was successfully isolated from a soil sample by inhibiting typical extracellular α-amylases using a proteinaceous α-amylase inhibitor. G3Amy was purified from the MK-1785 culture supernatant and characterized. G3Amy produced maltotriose as the principal product from starch and was categorized as an exo-α-amylase. G3Amy could also transfer maltotriose to phenolic and alcoholic compounds. Therefore, G3Amy can be useful for not only maltotriose manufacture but also maltooligosaccharide-glycoside synthesis. Further, the G3Amy gene was cloned and expressed in Escherichia coli cells. Analysis of its deduced amino acid sequence revealed that G3Amy consisted of an N-terminal GH13 catalytic domain and two C-terminal repeat starch-binding domains belonging to CBM20. It is suggested that natural G3Amy was subjected to proteolysis at N-terminal region of the anterior CBM20 in the C-terminal region. As with natural G3Amy, recombinant G3Amy could produce and transfer maltotriose from starch.
authors.affiliation: Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamon
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Sumitani
authors.forename: Shuji
authors.initials: S
authors.lastname: Tani
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: M
authors.initials: M
authors.lastname: Kamon
authors.forename: J
authors.initials: J
authors.lastname: Sumitani
authors.forename: S
authors.initials: S
authors.lastname: Tani
authors.forename: T
authors.initials: T
authors.lastname: Kawaguchi
mesh_terms: D000681:Amylases / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D006868:Hydrolysis; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013213:Starch / Q000378:metabolism; D013306:Streptomycetaceae / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D014312:Trisaccharides / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D014312:Trisaccharides; C008317:maltotriose; D013213:Starch; D000681:Amylases