作　　者： ; ; ; ; ; ; ;

机构地区： 中国水产科学研究院珠江水产研究所

出　　处： 《农业生物技术学报》 2010年第1期66-74,共9页

摘　　要： 本研究结合RT-PCR和RACE法获得了奥利亚罗非鱼(Oreochromis aureus)三种C型溶菌酶基因C-1,C-2和C-3的全长cDNA。3个基因的cDNA分别为581bp、662bp和695bp,各编码143、156和143个氨基酸(GenBank accession No:EU913095,EU913094和EU836689),相互间氨基酸序列的同源性在63.9%～67.8%之间。3个基因均具有与其它物种C型溶菌酶相同的8个保守半胱氨酸残基和2个活性位点Glu35和Asp52,可认为它们均为C型溶菌酶基因。在系统进化树中这3个基因首先与同属高等真骨鱼类的聚类,最后再与低等真骨鱼类的聚类,系统进化关系与传统鱼类分类地位相吻合,显示真骨鱼类C型溶菌酶的进化速度与物种的进化速度基本一致。蛋白分析软件分析显示这3个基因均具有C型溶菌酶的典型结构、相似的蛋白二、三级结构,推测应具有与C型溶菌酶相似的生理功能。但3个基因氨基酸序列间存在一定差异,其中C-1的等电点较低且碱性氨基酸较少,因此3种溶菌酶可能具有生理功能上的差异与分工。 Total RNA was isolated from livers of Oreochromis aureus and three chicken-type（C-type） lysozyme cDNAs,C-1,C-2 and C-3 were obtained by RT-PCR and RACE methods（GenBank accession No.：EU913095,EU913094 and EU836689）.The whole cDNA length of C-1 was 581 bp,consisting of a 432 bp open reading frame（ORF） which encoded 143 amino acids.The C-2 cDNA was 662 bp in length,consisting of a 471 bp ORF which encoded 156 amino acids.The C-3 cDNA was 695 bp,consisting of a 432 bp ORF which encoded 143 amino acids.The amino acid sequence identities between C-1 and C-2,C-1 and C-3,C-2 and C-3 were 67.8%,65.7% and 63.9%,respectively.ClustalW analyses showed that all the three genes possessed two conserved catalytic sites in mature peptide,Glu35 and Asp52,and 8 structural cysteine residues which were highly conserved across species of C-type lysozymes.Therefore these 3 genes were presumed to be members of C-type lysozyme.BLASTN analyses showed that the amino acid sequences of the three genes shared highly identity to Takifugu rubripes,Scophthalmus rhombus and Paralichthys olivaceus.In phylogenetic tree constructed based on lysozyme amino acid sequences,the 3 genes were firstly grouped to those of higher teleosteans,Pleuronectiformes and Tetraodontiformes fishes,and clustered to those of lower teleosteans,cypriniformes fishes at last.The consistence of the phylogenetic tree with traditional taxonomic results suggested that the evolution speed of C-type lysozyme in teleosteans accorded with the speed of species evolution.Bioinformatic analysis of mature peptide showed that the genes possessed typic sequence characteristics,secondary and tertiary structure of C-type lysozymes.The 3 genes could be presumed to possess physiological functions similar to C-type lysozyme.Certain difference existed among the deduced amino acid sequences of the three genes.C-1 was found to have a lower pI and less basic amino acids which suggested that these three lysozymes may possess different biological functions.

关 键 词： 奥利亚罗非鱼 型溶菌酶 蛋白质高级结构

领　　域： [农业科学]