• 제목/요약/키워드: Thermus brockianus

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Cloning and Overexpression of 4-${\alpha}$-Glucanotransferase from Thermus brockianus (TBGT) in E. coli

  • Bang, Bo-Young;Kim, Han-Jo;Kim, Hae-Yeong;Baik, Moo-Yeol;Ahn, Soon-Cheol;Kim, Chung-Ho;Park, Cheon-Seok
    • Journal of Microbiology and Biotechnology
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    • 제16권11호
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    • pp.1809-1813
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    • 2006
  • A gene corresponding to 4-${\alpha}$-glucanotransferase (${\alpha}GTase$) was cloned from the thermophilic bacterium Thermus brockianus. The nucleotide sequence analysis showed that the ${\alpha}GTase$ gene is composed of 1,503 nucleotides and encodes a polypeptide that is 500 amino acids long with a calculated molecular mass of 57,221 Da. The deduced amino acid sequences of Thermus brockianus ${\alpha}GTase$ (TBGT) exhibited a high level of similarity to the amino acid sequence of ${\alpha}GTase$ of Thermus thermophilus (86%), but low level of homology to that of E. coli (26%). The TBGT gene was overexpressed in E. coli BL21, and the corresponding recombinant enzyme was efficiently purified by Ni-NTA affinity chromatography. The enzymatic characteristics revealed that optimal pH and temperature were pH 6 and $70^{\circ}C$, respectively. Most interestingly, TBGT reacted with small oligosaccharides, especially maltotriose, to form various maltooligosaccharides by using its disproportionation activity.