摘要:
为了在蛋白表达水平上了解银杏(Ginkgo biloba)基于年龄变化的叶片蛋白质表达特征,寻找与年龄变化相关的响应蛋白,以楼观台老子手植银杏(约2 600年生)、说经台银杏(约800年生)和20年生幼龄银杏的叶片为研究对象,利用双向凝胶电泳(2-DE)和MALDI TOF/TOF MS/MS技术研究3个树龄银杏叶片蛋白质差异表达.蛋白质2-DE凝胶图谱经PD-Quest 8.0软件分析与检测分别得到340、341和410个点形规则清晰、可重复的蛋白点,这些蛋白点的分子质量大多分布在20~50 ku(占70%),等电点主要集中分布在pH 5~6.5(占75%);选取37个差异显著蛋白质凝胶点进行MALDI TOF/TOF MS/MS鉴定分析,成功鉴定30个蛋白质点,经过功能注释得出这些蛋白质主要参与能量及碳水化合物代谢(40%)、蛋白及氨基酸合成代谢(20%)及光合作用(16.7%)等途径;通过聚类分析得到基于年龄变化的蛋白质差异表达图谱,在高龄银杏叶片中上调表达的蛋白有11个,主要与光合作用、蛋白质及氨基酸代谢有关,下调表达的有8个,主要参与植物的能量及碳水化合物代谢.本研究明确了不同树龄银杏叶片差异蛋白参与的代谢途径,为进一步从分子水平深入了解银杏抗衰老的机理提供了理论基础.%In order to understand the protein expression on leaves of Ginkgo biloba with different ages and to look for the responded proteins and their age-based changes,the leaves from Ginkgo tree with three age stages (2600-,800-,and 20-year-old) were collected to conduct the differential proteomics by two-dimensional gel electrophoresis (2-DE) and MALDI TOF/TOF MS/MS.PD-Quest 8.0 software was used to analyze the profiles of 2-DE gels,from which 340,341,and 410 clear and regular reproducible protein spots were detected from the three-age groups,respectively.The molecular weights of detected protein spots were mostly between 20 and 50 ku (70%) and the isoelectric points were mainly distributed in the pH 5 ~6.5 (75%).Thirty seven significantly and differentially expressed protein spots were selected for MALDI TOF / TOF MS/MS and 30 protein spots were successfully identified.The majority of the identified protein species was classified into functional categories,including energy and carbohydrate metabolism (40%),protein and amino acid synthesis (20%) and photosynthesis (16.7%).The expression patterns of the identified proteins were analyzed by clustering analysis.From the leaves of aged trees,there were upregulated 11 protein species with functions in photosynthesis,protein and amino acid synthesis.However,8 down-regulated proteins were mainly related to energy and carbohydrate metabolism.This study clarified the metabolic pathways which differentially expressed proteins of the leaves from Ginkgo at different ages involved in and provided a theoretical basis for further understanding theanti-aging mechanism of Ginkgo at molecular level.