Applied Microbiology and Biotechnology

, Volume 79, Issue 2, pp 225–233

Cloning of a rumen fungal xylanase gene and purification of the recombinant enzyme via artificial oil bodies

Authors

    • Department of Animal Science and Technology, Institute of BiotechnologyNational Taiwan University
    • Institute of BioAgricultural SciencesAcademia Sinica
  • Xin Zhao
    • Department of Animal ScienceMcGill University
  • Jason T. C. Tzen
    • Graduate Institute of BiotechnologyNational Chung-Hsing University
  • Kuo-Joan Cheng
    • Institute of BioAgricultural SciencesAcademia Sinica
  • Cheng-Kang Pai
    • Department of Life ScienceNational Taiwan Normal University
Biotechnologically Relevant Enzymes and Proteins

DOI: 10.1007/s00253-008-1418-1

Cite this article as:
Liu, J., Duan, C., Zhao, X. et al. Appl Microbiol Biotechnol (2008) 79: 225. doi:10.1007/s00253-008-1418-1

Abstract

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°C; at temperatures below 30 and above 55°C, enzyme activity was less than 50% of that at the optimal temperature.

Keywords

RumenNeocallimastix patriciarumXylanaseArtificial oil body

Copyright information

© Springer-Verlag 2008