中介蝮蛇毒L-氨基酸氧化酶基因的生物信息学分析  

Bioinformatics analysis of SV-LAO gene fromGloydius intermedius

作　　者：张翠[1] 郭积芳 孙悦[1] 王芳霞[1] 杨章民[1] 

机构地区：[1]陕西师范大学生命科学学院,陕西西安710119

出　　处：《陕西师范大学学报（自然科学版）》2015年第5期71-75,共5页Journal of Shaanxi Normal University：Natural Science Edition

基　　金：国家自然科学基金(30870303);中央高校基本科研业务费专项资金(GK200902029);国家大学生创新训练计划(CX14067)

摘　　要：采用生物信息学方法,对中介蝮蛇毒L-氨基酸氧化酶（GI-LAO）基因进行了分析。结果表明：GI-LAO基因所包含的开放阅读框为1 515bp,编码504个氨基酸残基;GI-LAO一级结构与白眉蝮GH-LAO的相似性最高,达99%;N-端的18个氨基酸残基为信号肽,成熟肽含486个氨基酸残基,相对分子质量为55.1kDa,理论等电点为6.55;该蛋白含有两个结构域：FAD结合域（56-123位氨基酸残基）和催化结构域（61~499位氨基酸残基）;与白眉蝮GH-LAO序列比对发现,有4个氨基酸位点存在差异（分别是20、56、99和467位氨基酸残基）,用SIFT软件分析表明,这四个位点对其功能无影响;该基因编码的氨基酸序列有2个活性位点（H242和R343）,2个N-糖基化位点（N190和N379）,5个位点（R108、H241、Y390、G482和W483）与底物结合有关,4个保守半胱氨酸残基形成两对二硫键（C28—C191和C349—C430）;三维结构建模结果表明,GI-LAO形成同源二聚体,每个单体由22个α-螺旋,22个β-折叠股和一些无规则卷曲、转角等形成三个结构域：FAD结合域,底物结合域以及α-螺旋域;在GI-LAO蛋白的进化分析中,中介蝮GI-LAO与白眉蝮GHLAO的亲缘关系最近。A snake venom L-amino acid oxidase（SV-LAO）gene fromGloydius intermedius cDNA library was bioinformatically analyzed.The results showed that the open reading frame of cDNA is 1 515 bp,encoding 504 amino acids.The primary structures of LAOs between Gloydius halys and Gloydius intermedius showed the highest identity（99%）.The N-terminal 18 amino acids is the signal peptide,so the mature peptide contains 486 amino acids,with the theoretical molecular weight and isoelectric point being 55.1kDa and 6.55,respectively.GI-LAO contains two domains,ie.FAD binding domain and catalytic domain.A comparison of the primary structures between GI-LAO with GH-LAO（LAO of Gloydius halys）revealed that there are four amino acids differences（20,56,99 and 467）.Online analysis with SIFT software indicated that these differences have no influence on the function of GI-LAO.The key residues in the active site are H242 and R343.The potential N-glycosylation sites are N190 and N379.Five residues（R108,H241,Y390,G482,W483）form the substrate binding sites.The four conserved Cys residuces are presumably to form two disulfide bonds（C28—C191and C349—C430）.Tertiary structure remodel-ling revealed that GI-LAO is composed of 22ɑ-helixes,22β-strands,turns and loops,which may then refold into three domains（the FAD-binding domain,the substrate-binding domain and theα-helical domain）.The GI-LAO protein phylogenetic tree indicates a closest relationship between Gloydius halys and Gloydius intermedius.These bioinformatical analysis would lay the foundation for further investigation of GI-LAO as anti-viral agent.

关 键 词：中介蝮 L-氨基酸氧化酶 基因 生物信息学 

分 类 号：Q811.4[生物学—生物工程] Q71