‘航花2号’的Δ^(12)脂肪酸脱氢酶(FAD2)基因的生物信息学分析

Bioinformatic Analysis of Delta-12 Fatty Acid Desaturase 2( FAD2)

植物中的Δ12脂肪酸脱氢酶(FAD2)是油酸形成亚油酸的关键酶。通过NCBI和EXPASY 2大数据库,采用Signal P、TMHMM、Psort、Prot Param和Target P等分析程序对花生品种‘航花2号’及其它物种的19个FAD2蛋白序列进行分析,利用MEGA6.0软件比对序列及构建系统进化树阐明FAD2基因的系统发育关系,亲缘相近的FAD2蛋白聚在一起。预测了‘航花2号’和‘粤油13’的FAD2蛋白的分子质量、等电点、信号肽、跨膜和保守结构域等。结果表明:‘航花2号’FAD2蛋白的N端没有信号肽,预测定位在微体、细胞质、线粒体基质和叶绿体类囊膜中,而C端信号基序LKGL使得FAD2蛋白选择性地结合和嵌入内质网,植物的FAD2蛋白普遍有3个高度保守的组氨酸富集基序(HECGHH、HRRHH和H[A/C/T]HH)和3~5个跨膜结构,但分析结果显示,‘航花2号’的FAD2蛋白的H[A/C/T]HH的组氨酸基序是缺失的,而油酸转化为亚油酸的效率上并没有显著变化,为将来FAD2基因的基因工程操作提供一定的理论基础。

Delta-12 fatty acid desaturase 2 （FA D2） was a key enzyme to insert oleic acid to linoleic acid. Through the NCBI and EXPASY 2 database, nineteen FAD2 protein sequences from peanut Hanghua 2 and other species of plants were analyzed by SignalP, TMHMM, Psort, ProtParam and TargetP procedures. The phylogenetic relationship of FAD2 was elucidated by neighbour-joining tree and MEGA6.0. FAD2 proteins with high similarity sequence were clustered. The molecular mass, isoelectric point, signal peptide, trans-membrane and conserved domains of FAD2 protein were predicted for peanut Hanghua 2 and Yueyou 13. The results showed that there was no signal peptide of N-terminal of FAD2 in Huanghua 2. The FAD2 proteins were predicted in microbody, cytoplasm, mitochondrial matrix space and chloroplast thylakoid membrane. C-terminal signaling motif LKGL allows FAD2 proteins to selectively bind and embed in the endoplasmic reticulum. The FAD2 proteins included three highly conserved histidine-rich motifs （HECHH, HRRHH and HV [A/C/T]HH） and three to five transmembrane anchors. But C-terminal of FAD2 in Huanghua 2 was lack of HV[A/C/T]HH histidine motif. No change was observed in efficiency of insertion of oleic acid to linoleic acid. This could be used for genetic engineering of FA D2 gene in the future.