木聚糖酶基因xyn I的克隆和序列分析

Cloning and Sequence Analysis of the xyn I Encoding Xyn I from Aspergillus usamii E001

以宇佐美曲霉E001总RNA为模板,采用RT-PCR等技术扩增了木聚糖酶基因(xynI)的cDNA全序列(GenBank登录号DQ302412)。该cDNA全长881 bp,其中5′和3′端非编码区分别为97和106 bp,信号肽编码区111 bp,成熟肽编码区567 bp编码188个氨基酸组成的木聚糖酶Xyn I。以E001基因组DNA为模板,采用单侧PCR等技术扩增了xynI的DNA全序列(GenBank登录号DQ302413)。该DNA全长1 098 bp,含启动子序列、内含子和外显子等核苷酸序列。将xynI cDNA所推导的Xyn I一级结构与GenBank中报道的其它相关序列进行了同源性比较。结果表明,E001 Xyn I是一种新的木聚糖酶,且具有第G/11家族木聚糖酶的共同特征。

The xyn Ⅰ cDNA （GenBank, DQ302412） was amplified with RT-PCR methods from the total RNA extracted from Aspergillus usamii E001. Sequence analysis showed that the cDNA is 881 bp in length including 5′ and 3′non-encoding regions, a 111 bp signal peptide encoding region,and a 567 bp mature peptide encoding region which encoded the xylanase （Xyn Ⅰ） of 188 amino acids. The xylanase gene （xyn Ⅰ） DNA （GenBank, DQ302413） was amplified with signal primer PCR methods from the genomic DNA extracted from E001. The DNA is 1 098 bp in length which included the regions of a promoter, a intron and two exons. Comparison of the homologies of the amino acid sequence of the Xyn Ⅰ with other xylanases from GenBank was carried out. The results showed that the Xyn Ⅰ is a new xylanase and belongs to G/11 family.