title: Nanosilica sol leads to further increase in polyethylene glycol (PEG) 1000-enhanced thermostability of β-cyclodextrin glycosyltransferase from Bacillus circulans.
abstract: A major disadvantage of cyclodextrin production is the limited thermostability of cyclodextrin glycosyltransferase. The ability of combinations of nanosilica sol with polyethylene glycol (PEG) 1000 to enhance the thermostability of the β-cyclodextrin glycosyltransferase from Bacillus circulans was investigated. It was found that 10% PEG 1000 combined with 0.05% nanosilica sol could activate the β-cyclodextrin glycosyltransferase by 17.2%. Furthermore, 0.05% nanosilica sol leads to further increase in PEG 1000-enhanced thermostability of β-cyclodextrin glycosyltransferase. With the simultaneous addition of 10% PEG 1000 and 0.05% nanosilica into the enzyme solution, which was allowed to incubate for 60 min at 60 °C, 61.3% of β-cyclodextrin-forming activity could be retained, which was much higher than that with only 10% PEG 1000 added. Atomic force microscopy, fluorescence spectroscopy, and circular dichroism analysis indicated that silica nanoparticles helped PEG 1000 further protect the tertiary and secondary structures of β-cyclodextrin glycosyltransferase. This study provides an effective approach for improving the thermostability of cyclodextrin glycosyltransferase and related enzymes.
authors.affiliation: State Key Laboratory of Food Science and Technology, ‡School of Food Science and Technology, and §Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University , Wuxi 214122, People's Republic of China.
authors.forename: Caiming
authors.initials: C
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.forename: Zhengbiao
authors.initials: Z
authors.lastname: Gu
authors.forename: Yan
authors.initials: Y
authors.lastname: Hong
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.forename: Zhaofeng
authors.initials: Z
authors.lastname: Li
mesh_terms: D001407:Bacillus / Q000737:chemistry / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001671:Biochemistry / Q000379:methods*; D004795:Enzyme Stability; D005964:Glucosyltransferases / Q000737:chemistry* / Q000378:metabolism; D006358:Hot Temperature; D011092:Polyethylene Glycols / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase