| Title | 초고온 고세균 Thermococcus pacificus P-4로부터 내열성 β-glucosidase의 새로운 기질 특이성 | ||
| Author | 김윤재1,2, 이재은1, 이현숙1,2, 권개경1,2, 강성균1,2, and 이정현1,2* | ||
| Address | 1한국해양과학기술원, 2과학기술연합대학원대학교 해양생명공학부 | ||
| Bibliography | Korean Journal of Microbiology, 51(1),68-74, 2015 | ||
| DOI | http://dx.doi.org/10.7845/kjm.2015.5003 | ||
| Key Words | β-1,3-linked polysaccharide, β-glucosidase, Thermococcus pacificus P-4, exo-hydrolyzing activity, laminarinase activity | ||
| Abstract | Based on the genomic analysis of Thermococcus pacificus P-4, we identified a putative GH1 β-glucosidase-encoding gene (Tpa-glu). The gene revealed a 1,464 bp encoding 487 amino acid residues, and the deduced amino acid residues exhibited 77% identity with Pyrococcus furiosus β-glucosidase (accession no. NP_577802). The gene was cloned and expressed in Escherichia coli system. The recombinant protein was purified by metal affinity chromatography and characterized. Tpa-Glu showed optimum activity at pH 7.5 and 75°C, and thermostability with a half life of 6 h at 90°C. Tpa-Glu exhibited hydrolyzing activity against various pNP-glycopyranosides, with kcat/Km values in the order of pNP-β-glucopyranoside, pNP-β-galactopyranoside, pNP-β-mannopyranoside, and pNP-β-xylopyranoside. In addition, the enzyme exhibited exo-hydrolyzing activity toward β-1,3-linked polysaccharide (laminarin) and β-1,3- and β-1,4-linked oligosaccharides. This is the first description of an enzyme from hyperthermophilic archaea that displays exo-hydrolyzing activity toward β-1,3-linked polysaccharides and could be applied in combination with β-1,3-endoglucanase for saccharification of laminarin. | ||
| Download PDF | 51(1)_09_p.68-74.pdf | ||