Cloning and expression of inulin fructotransferase gene of Arthrobacter sp. A-6 in Escherichia coli and Bacillus subtilis

The inulin fructotransferase (depolymerizing) (IFTase, EC 2.4.1.93) gene of Arthrobacter sp. A-6 was cloned and expressed in Escherichia coli and Bacillus subtilis. The IFTase gene consisted of an ORF of 1,311 nucleotides encoding a polypeptide of 436 amino acids containing a signal peptide of 31 amino acids in the N-terminus. The molecular mass of the IFTase based on the nucleotide sequence was calculated to be 46,116 Da. The recombinant E. coli DH5α cells expressing the Arthrobacter sp. A-6 IFTase gene produced most of the IFTase intracellularly. In contrast, the recombinant B. subtilis DB 104 carrying the IFrase gene on a B. subtilis-E. coli expression vector secreted the IFrase into the culture fluid efficiently.