目的 克隆三萜皂苷代谢关键酶竹节参β-香树素合成酶（β-AS）基因，采用生物信息学分析其序列及其结构与功能，为竹节参合成及调控机制研究提供基础。方法 提取竹节参叶片RNA，扩增β-AS基因编码区序列，将序列连接至pMDTM18-T载体进行克隆、测序，并利用生物信息学分析比较移栽品和栽培品竹节参β-AS蛋白的特征，构建竹节参β-AS蛋白的系统进化树。结果 克隆出移栽品和栽培品竹节参的β-AS基因编码区序列，开放阅读框（ORF）均为2 286 bp，编码761个氨基酸。2个品种β-AS蛋白在细胞中的基本结构和功能是一致的，但两者之间存在8个氨基酸差异，使两者的蛋白质二级结构、三级结构磷酸化位点以及理化性质存在差异，可能会导致两者的催化活性存在差异。结论 克隆得到野生移栽品和栽培品竹节参的β-AS基因，并对2个品种β-AS蛋白进行了生物信息学分析和比较，为今后研究该酶的结构特征、功能以及其与皂苷含量的相关性提供参考，也为竹节参合成生物学研究提供了生物基因元件。

Objective The key enzyme of triterpene saponin metabolism was cloned and its sequence, structure and function were analyzed by bioinformatics. Methods RNAs were extracted from the leaves of Panax japonicus The full-length cDNA sequences of β-AS were cloned by utilizing RT-PCR method, and the sequence was connected to the pMDTM18-T for cloning and sequencing.β-AS protein characteristics in transplanted species and cultivated species of P. japonicus were predicted and compared by bioinformatics analysis and the phylogenetic tree of β-AS protein was constructed. Results The β-AS sequences in transplanted species and cultivated species of P. japonicus were obtained, which had 2 286 bp ORF and encoded 761 amino acids. There were little differences between the two varieties of β-AS proteins in physicochemical properties, secondary structure, tertiary structure, and phosphorylation sites, which may lead to show difference in catalytic activity. Conclusion This work also obtained the full-length of cDNA sequence of β-AS gene in transplanted and cultivated varieties of P. japonicus, and provided a systemic sequence analysis of β-AS proteins, which can provide the useful information for β-AS studies in the future.

R282.12

国家自然科学基金资助项目（81673675）