眼镜王蛇泛素融合蛋白基因和核糖体蛋白L30基因的克隆及分析

Molecular Cloning and Comparison of Ubiquitin Fusion Protein and Ribosomal Protein L30 from Ophiophagus hannah

从广西产眼镜王蛇(Ophiophagushannah)毒腺中抽提总RNA,经mRNA纯化后构建眼镜王蛇毒腺cDNA文库。从所构建的cDNA文库中,随机筛选200个克隆测序,得到两个在进化上高度保守的基因:泛素融合蛋白基因(GenBank登录号为AF297036)和核糖体蛋白L30基因(GenBank登录号是AF297033)。前者cDNA的开放阅读框为387bp,后者为348bp。前者编码128个氨基酸残基组成的泛素融合蛋白前体;后者编码115个氨基酸残基组成的核糖体蛋白L30前体。由cDNA序列推导出的氨基酸序列分析表明,泛素融合蛋白前体包括N-末端的泛素结构域(76个氨基酸残基)和C-末端的核糖体蛋白L40结构域(52个氨基酸残基)。该蛋白为一高碱性蛋白,C末端含有一个“锌指”模式结构。与16个物种比较的结果表明,眼镜王蛇与脊椎动物的泛素融合蛋白氨基酸序列相似度较高,具有高度的保守性。

Total RNA was extracted trom the venom gland ot snake Ophiophagus hannah. A king cobra venom gland cDNA library was then constructed using purified mRNA from the total RNA. By random sequencing of 200 independent clones, two conserved cDNA sequences of house-keeping genes were obtained. One is ubiquitin fusion protein （GenBank accession number AF297036） ; the other is ribosomal protein L30 （GenBank accession number AF297033）. The former has an open reading frame of 387 bp, encoding a 128 amino acid ubiquitin fusion protein precursor composed of a 76 amino acid ubiquitin domain and followed by a 52 amino acid ribosomal protein L40 domain. The deduced precursor protein from the nucleotide sequence is basic. The C-terminus of the ubiquitin fusion protein contains the zinc-finger motif. The latter has an open reading frame of 348 bp, encoding for 115 amino acid ribosomal protein L30 precursor. The predicted amino acid sequence of ubiquitin fusion protein is highly conserved when compared to the sequences of homologous proteins from sixteen diverse species.