Cloning, Expression, and Transglycosylation Reaction of Paenibacillussp. Strain W-61 Xylanase 1

A xylanase gene, xyn1, which encodes Paenibacillussp. strain W-61 xylanase 1 (Xyn1), was cloned in Escherichia coli. xyn1encodes 211 amino acid residues, including 28 amino acid residues of a signal peptide. The deduced amino acid sequence of the mature Xyn1 showed 95.7%, 84.0%, and 83.7% identity to family 11 xylanases of Aeromonas caviaeME-1, Paenibacillussp., and Bacillus stearothermophilusrespectively. The physico-chemical properties of recombinant Xyn1 were very similar to those of intact Xyn1, except for the molecular mass. The pattern of xylooligosaccharides generated by rXyn1 was investigated by fluorophore-assisted carbohydrate electrophoresis (FACE). The degradation rate of xylohexaose by rXyn1 increased markedly as compared with that of xylopentaose. Xylohexaose had a single preferential point of cleavage by rXyn1. On the basis of the pattern of action of xylooligosaccharides, the number of subsites was estimated to be six. The catalytic site was located between the third and the fourth subsites from non-reducing end.