【摘要】 利用Gen Bank中已登录的完整的麻风树、乳浆大戟、蓖麻和乌桕中的13个蓖麻烯合酶(Casbene synthase,CS;EC 4.6.1.7)基因序列,通过生物信息学方法对其核酸及氨基酸序列、组成成分、导肽、信号肽、跨膜结构域、疏水性/亲水性、蛋白质的二级结构、三级结构及功能域等进行了分析预测。结果表明,13个CS基因的ORF长度均在1 647~1 845 bp,蛋白分子量均在63.0~70.8 k D,终止密码子为TGA或TAA,理论等电点均小于7.0,表明CS蛋白呈酸性。氨基酸含量最高的均为亮氨酸。核苷酸同源性比较分析表明,CS基因主要分为两类。导肽预测发现其中6个CS具有导肽,均为叶绿体导肽。信号肽和扩模结构域预测发现这些CS不存在信号肽和跨膜结构域,肽链整体呈现为亲水性。这些CS的主要二级结构元件为α-螺旋,并且都包含两个萜类合酶功能域。以上研究为进一步探索CS基因的功能提供一定理论依据。更多还原

【Abstract】 We used bioinformatics to study 13 casbene synthase( CS; EC 4. 6. 1. 7) full-length gene sequences registered in the Gen Bank from Euphorbia esula,Jatropha curcas L.,Ricinus communis and Triadica sebifera,and predicted the composition of nucleic acid and amino acid sequences,leader peptides,signal peptide,transmembrane topological structure,hydrophobicity or hydrophilicity,the secondary and tertiary structure as well as the function domains. The 13 genes encoding ORFs were 1 647- 1 845 bp,the molecular weight of the 13 predicted proteins were 63. 0- 70. 8 k D,and the termination codons were TGA or TAA. The theoretical isoelectric points of the 13 proteins were lower than 7. 0,which suggested that CS proteins were acidic. Leu was the most contented amino acid. By the homologous alignment of nucleic acid,CS genes were divided into two groups. The prediction of leading peptides showed that at least 6 CSs had leader peptide( chloroplast leader peptide mainly) in common. All 13 CSs had no signal peptide and trans-membrane topological structure in and the peptide chains were hydrophilicity. α-helix was the dominant secondary structure constructional element of the 13 proteins which contained two terpenoid synthases function domains.更多还原