title: Cloning and extracellular expression of inulin fructotransferase from Arthrobacter aurescens SK 8.001 in E. coli.
abstract: BACKGROUND
  Difructose anhydride (DFA) III is a natural and low-calorie sweetener. It stimulates the absorption of calcium and other minerals. Inulin fructotransferase (IFTase; EC 4.2.2.18), catalysing inulin hydrolysis to DFA III, is considered to be the most promising enzyme for the production of DFA III.
  
  
  RESULTS
  IFTase gene from Arthrobacter aurescens SK 8.001 was cloned and sequenced. Transformant with native IFTase signal peptide was a useful system for extracellular over-expression of IFTase, and its extracellular IFTase activity reached 81.0 U mL(-1) . This value was 4.1-fold of that obtained with A. aurescens SK 8.001 for IFTase production. The recombinant IFTase was purified to electrophoretical homogeneity and characterized. The enzyme showed maximum activity at pH 6.0 and 55 °C, and retained 81.3% of its initial activity after incubation at 60 °C for 4 h.
  
  
  CONCLUSIONS
  IFTase gene from A. aurescens SK 8.001 was cloned, sequenced and over-expressed in E. coli. IFTase was reported for the first time to be over-expressed extracellularly. The recombinant IFTase was purified and characterized, and shown to be a good candidate for potential application in DFA III production.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.forename: Wanmeng
authors.initials: W
authors.lastname: Mu
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Hua
authors.initials: H
authors.lastname: Hang
authors.forename: Liuming
authors.initials: L
authors.lastname: Zhou
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D001173:Arthrobacter / Q000201:enzymology*; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D004187:Disaccharides / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006602:Hexosyltransferases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007444:Inulin / Q000378:metabolism*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013549:Sweetening Agents / Q000138:chemical synthesis / Q000378:metabolism*; D013696:Temperature
chemical_list: D004187:Disaccharides; D011994:Recombinant Proteins; D013549:Sweetening Agents; C087758:difructose anhydride III; D007444:Inulin; D006602:Hexosyltransferases