巴西橡胶树β-木糖苷酶基因的克隆与生物信息学分析

Cloning and Bioinformatic Analysis of the Gene EC32 from Hevea brasiliensis

以巴西橡胶树根为材料,利用RT-PCR技术从总RNA中捕获到一个β-木糖苷酶家族基因（β-xylosidase或β-D-xyloside xylohydrolase,EC 3.2.1.37）,cDNA长度2 880 bp,开放阅读框2 319 bp,编码773个氨基酸,命名为HbEC32。在HbEC32氨基酸序列中具有一个较强的跨膜区,二级结构分析表明其属于混合型蛋白。HbEC32在N端前8～20氨基酸区域内为较强的疏水区,但整条多肽链表现为亲水性。对15个β-木糖苷酶蛋白进行系统进化分析发现,巴西橡胶树的HbEC32基因与蓖麻亲缘关系最近。

A novel full-length β-D-xyloside xylohydrolase gene named HbEC32 was obtained by using reverse transcription-polymerase chain reaction（RT-PCR） from total RNA from the root of Hevea brasiliensis. HbEC32 was 2 880 bp long containing a 2 319-bp open reading frame（ORF）, which encoded 773 amino acids. One strong transmembrane structure was predicted within HbEC32. The result of secondary structure predicted showed that the protein was classified as mixed type. There was a strong hydrophobic region in the N-terminal 8-20 amino acids of HbEC32, but the entire polypeptide chain was hydrophilic. The result of phylogenetic tree indicated that HbEC32 displayed a high degree of sequence similarity to RcEC32.