【摘要】 采用cDNA末端快速扩增的办法,从孔石莼(Ulva pertusa)中克隆获得质体蓝素基因。该基因完整的cDNA为787bp,包括40 bp 5’端非编码区和327 bp的3’端非编码区,以及一个420 bp的开放阅读框架,编码139个氨基酸的蛋白质。该基因编码质体蓝素的前体肽,其N端41个氨基酸残基为信号肽,后面为98个氨基酸残基的成熟肽。从Genbank中选择了13个质体蓝素的前体肽基因进行序列比对分析和构建进化树。孔石莼质体蓝素基因与其它质体蓝素基因的同源性为48.2%至78.8%。该进化树将来源于6种藻类植物的7个质体蓝素基因聚类在一起,显示出它们较近的进化关系。同样,也表现出11种生物的分子进化关系。序列比对结果显示,在质体蓝素的基因序列中存在两个高度保守的基序,它编码质体蓝素蛋白的铜结合活性位点。更多还原

【Abstract】 A plastocyanin precursor cDNA gene of Ulva pertusa was isolated with the method of rapid amplification of cDNA ends(RACK).The complete cDNA sequence covered 787 bp nucleotides including a 420 bp of open reading frame which encodes a putative plastocyanin precursor of 139 amino acid residues,a 40 bp 5 ’-terminal and a 327 bp 3’-terminal untranslated regions.The cDNA gene from U.pertusa shared homology from 48.2%to 78.8%with the 12 genes from 10 different species.A phylogenetic tree was constructed based on the 13 sequences of plastocyanin precursor genes from 11 species.7 plastocyanin gene sequences from 6 algae formed a cluster in the phylogenetic tree,indicating closely evolutionary relationship.The phylogenetic tree also revealed the molecular evolutionary relationship of the 11 species based on the 13 sequences analyses.Sequence alignments also represented two highly conserved motifs in the sequences, which encoded the copper-binding active sites of the plastocyanin protein.更多还原