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|標題:||Cloning of a rumen fungal xylanase gene and purification of the recombinant enzyme via artificial oil bodies||作者:||Liu, J.R.
|關鍵字:||rumen;Neocallimastix patriciarum;xylanase;artificial oil body;neocallimastix patriciarum;microbial xylanases;cellulase activity;catalytic-activity;binding modules;domains;linker;expression;bacteria;sequence||Project:||Applied Microbiology and Biotechnology||期刊/報告no：:||Applied Microbiology and Biotechnology, Volume 79, Issue 2, Page(s) 225-233.||摘要:||
A gene encoding a xylanase, named xynS20, was cloned from the ruminal fungus Neocallimastix patriciarum. The DNA sequence of xynS20 revealed that the gene was 1,008 bp in size and encoded amino acid sequences with a predicted molecular weight of 36 kDa. The amino acid sequence alignment showed that the highest sequence identity (28.4%) is with insect gut xylanase XYL6805. According to the sequence-based classification, a putative conserved domain of glycosyl hydrolase family 11 was detected at the N-terminus of XynS20 and a putative conserved domain of family 1 carbohydrate-binding module (CBM) was observed at the C-terminus of XynS20. An Asn-rich linker sequence was found between the N-terminal catalytic domain and the C-terminal CBM of XynS20. To examine the activity of the gene product, xynS20 gene was cloned as an oleosin-fused protein, expressed in Escherichia coli, affinity-purified by formation of artificial oil bodies, released from oleosin by intein-mediated peptide cleavage, and finally harvested by concentration of the supernatant. The specific activity of purified XynS20 toward oat spelt xylan was 1,982.8 U mg(-1). The recombinant XynS20 was stable in the mild acid pH range from 5.0 to 6.0, and the optimum pH was 6.0. The optimal reaction temperature of XynS20 was 45 degrees C; at temperatures below 30 and above 55 degrees C, enzyme activity was less than 50% of that at the optimal temperature.
|Appears in Collections:||生物科技學研究所|
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