Title Molecular Cloning and Expression of a Thermostable Xylose (Glucose) Isomerase Gene, xylA, from Streptomyces chibaensis J-59
Author Gil-Jae Joo, Jae-Ho Shin 1, Gun-Young Heo1, Young-Mog Kim, and In-Koo Rhee 1,*
Address Institute of Agricultural Science & Technology, Kyungpook National University, Daegu 702-701, Republic of Korea , 1Department of Agricultural Chemistry , Kyungpook National University, Daegu 702-701, Republic of Korea
Bibliography Journal of Microbiology, 43(1),34-37, 2005,
DOI
Key Words Streptomyces chibaensis, xylose (glucose) isomerase, xylA
Abstract In the present study, the xylA gene encoding a thermostable xylose (glucose) isomerase was cloned from Streptomyces chibaensis J-59. The open reading frame of xylA (1167 bp) encoded a protein of 388 amino acids with a calculated molecular mass of about 43 kDa. The XylA showed high sequence homology (92% identity) with that of S. olivochromogenes. The xylose (glucose) isomerase was expressed in Escherichia coli and purified. The purified recombinant XylA had an apparent molecular mass of 45 kDa, which corresponds to the molecular mass calculated from the deduced amino acid and that of the purified wild-type enzyme. The N-terminal sequences (14 amino acid residues) of the purified protein revealed that the sequences were identical to that deduced from the DNA sequence of the xylA gene. The optimum temperature of the purified enzyme was 85oC and the enzyme exhibited a high level of heat stability.
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