Cloning and sequence analysis of the gene encoding xylanase Xyn ZF-1 from Aspergillus niger XZ-3S

The cDNA of xylanase (Xyn ZF-1) gene was amplified from the Aspergillus niger XZ-3S total RNA by RT-PCR. The result showed that Xyn ZF-1 was 678bp in size and encoded 225 amino acids. The molecular weight and theoretical isoelectric point was 24.06ku and 5.20, respectively. The DNA of Xyn ZF-1 gene was amplified from the Aspergillus niger XZ-3S genmic DNA by PCR. The result confirmed that there was only one intron with the 68bp in length.The homology analysis of amino acid sequence shared 89.47% in base sequence with other microbial xylanase primary structure.Phylogenetic analysis showed that the enzyme belongd to glycosyl hydrolase family G/11. Besides, the secondary structure of Xyn ZF-1 was analysed, and three-dimensional structure of Xyn ZF-1 was predicted by SWISS-MODEL.