油桐亲环素基因全长cDNA的克隆及序列分析

Cloning and sequence analysis of full-length cDNA encoding cyclophilin in Vernicia fordii

亲环素基因广泛分布于各种生命体中,植物亲环素在植物生物学、胁迫应答、抗病原体免疫等方面起重要作用。根据油桐EST文库中的已知部分亲环素基因序列,通过5’RACE和RT-PCR,得到一个油桐亲环素全长cDNA序列。此基因全长为681 bp,包含一个长为519 bp的完整CDS,编码172个氨基酸,将该基因命名为vf_cyp。生物信息学分析表明,该基因编码的蛋白质相对分子量18 038.5 Da,理论等电点8.68。通过预测分析表明该蛋白无跨膜结构,不存在信号肽切割位点,二级结构以β折叠和无规卷曲为主,分别占36.05%和52.91%,具有典型的肽脯氨酰顺反异构酶活性区及植物亲环素基因特有的7个氨基酸插入序列KS/MGKPLH,通过亲缘进化分析表明油桐亲环素氨基酸序列与橙、杂柑、毛果杨亲环素基因的氨基酸序列相似性分别达到94%、94%、93%。

Cyclophilins are ubiquitously distributed in organisms,plant cyclophilins play an important roles in plant biology,stress response and anti-pathogen immunity.According to the part sequence of cyclophilin gene in seed EST library from Vernicia fordii,a fulllength cDNA encoding cyclophilin obtained with the method of RACE and RT-PCR.The length of Vernicia fordii cyclophilin is 681bp,contained a complete CDS of 519bp encoding 172 amino acids,named vf_cyp.The bioinformatics analysis indicated that the pI and MW of amino acids encoded by vf_cyp were predicted to be 8.68 and 18038.5Da respectively.The prediction result indicated membrane spaning domain and signal peptide were not exist in the protein,the secondary structure of the vf_cyp are β-sheet（36.05%） and Random coil（52.91%） primarily,the protein had one peptidyl-prolyl cis-trans isomerase binding domain,and containing the plant cyclophilins unique 7 amino acid insertion sequence KS/MGKPLH,the amino acid sequence of Vernicia fordii Cyclophilin showed similarities of 94%,94%,93% with those from Citrus sinensis,Citrus hybrid cultivar,Populus trichocarpa,respectively.