宇佐美曲霉木聚糖酶基因的克隆和序列分析

依据宇佐美曲霉(Aspergillus usamii)E001木聚糖酶(XynII)N末端氨基酸残基序列以及曲霉菌密码子的偏爱性和真核生物mRNA在3′端存在Poly(A)等所提供的生物信息,采用RTPCR技术扩增了XynII成熟肽和3′非编码区的cDNA片段,PCR产物直接克隆至pUCmT载体中。DNA序列分析表明,该cDNA全长733bp,其中3′非编码区178bp,成熟肽编码区555bp,编码184个氨基酸。成熟肽基因推导的氨基酸序列同Aspergillusniger、Emericellanidulans以及Trichodermaviride来源的木聚糖酶相比,同源性分别为89%、46%和36%。又进一步对XynII二级结构进行了分析,并通过SWISSMODEL预测了XynII的三维结构。

Cloning and Sequence Analysis of the Gene Encoding Xylanase Xyn Ⅱ from Aspergillus usamii

With the information of N-terminal amino acid sequence of Xyn II from Aspergillus usamii E001, the appropriate codon usage of Aspergillus and 3′-terminal poly(A) of eukaryotic mRNA, the Xyn II cDNA was amplified by RT-PCR, and cloned into the vector pUCm-T. Sequence analysis showed that the cDNA is 733 bp length including a 178 bp 3′-non-encoding region and a 555 bp encoding region, which encoded a polypeptide of 184 amino acids. The amino acid sequence homologies with Aspergillus niger,Emericella nidulans and Trichoderma viride were 89%,46%,36% respectively. Besides, the secondary structure of Xyn II was analysed, and three-dimensional structure of Xyn II was predicted by SWISS-MODEL.