【作者】 余庆波；

【导师】 周根余； 杨仲南；

【作者基本信息】 上海师范大学 ， 遗传学， 2005， 硕士

【摘要】 叶绿体是植物非常重要的细胞器,除了进行光合作用外,还参与了其他的生物代谢.在模式植物拟南芥中,叶绿体基因组编码87 个叶绿体蛋白,核基因组编码约4255 个叶绿体蛋白.绝大部分叶绿体蛋白的功能通过序列同源性分析确定,但是仍有约25%的蛋白质功能尚不清楚.本论文利用生物信息学方法并结合分子生物学方法对拟南芥叶绿体蛋白质功能进行研究.首先利用三种生物信息学的方法构建了叶绿体蛋白质相互作用数据库.其中利用平移法,将5 个物种的蛋白质相互作用数据平移到拟南芥中,共获得拟南芥叶绿体蛋白质相互作用8157对;利用系统进化谱法,共获得可能的叶绿体相互作用的数据19,652 对;利用基因芯片表达谱法,对两个基因表达系数为0.90 以上数据分析,共获相互作用数据65,299 对.然后我们对以上构建的拟南芥叶绿体蛋白相互作用数据进行分析。这些蛋白质相互作用对参与多种代谢途径,如蛋白质的转运,淀粉代谢,脂肪酸代谢,光合作用等.预测结果表明,多个未知蛋白质与光合作用四个复合体中的亚单位相互作用;叶绿体中FtSH 家族金属蛋白酶7 个成员之间有相互作用;与光合作用蛋白质磷酸化作用的激酶STN7 和STN8 相互作用的蛋白质多为蛋白质激酶,多数蛋白质激酶的生物功能未知.最后我们通过酵母双杂交实验验证部分蛋白质的相互作用。从所构建的拟南芥叶绿体蛋白质相互作用数据库中,选取了46 对与光合作用有关的蛋白质相互作用对进行实验验证,初步实验结果表明,一个未知蛋白质C 与光合系统I 的蛋白psaD2 存在相互作用,因此,该未知蛋白质C 可能与光合作用有关.该数据库将有助于我们深入开展拟南芥叶绿体系统生物学研究以及光合作用相关蛋白的功能挖掘.更多还原

【Abstract】 Chloroplast is a very important organelle of plant cells. Besides photosynthesis,it also carries out other essential metabolism. In model plant Arabidopsis thaliana, atotal of 87 chloroplast proteins are encoded by plastomes, and about 4255nulcear-encoded proteins are predicted to be located in chloroplast. The functions ofmost chloroplast proteins are identified based on sequence homology, and about 25%of chloroplast proteins are still unknown. In this dissertation, chloroplast proteinfunctions in Arabidopsis thaliana were investigated, using both bioinformatics andmolecular biology techniques. Firstly, a chloroplast protein interaction database wasconstructed using three bioinformatics methods. A total of 8157 pairs of chloroplastprotein interactions were predicted based on protein interlogs from data of other 5species; a total of 19652 pairs were predicted based on the phylogenetic profile; and atotal of 65299 pairs were predicted based on the expression level of genes from 79gene chips data downloaded from TAIR with the coefficient of the gene co-expressionmore than 0.9000. After the chloroplast protein interactions database was constructed,protein interactions in the database were analyzed. The protein pairs in the databasewere involved in metabolic pathways such as protein transport, starches, lipidmetabolites and photosynthesis. Our database also showed that some unknownproteins interact with subunits of four major complexes in photosynthesis, and mostproteins interacting with STN7 or STN8, which are responsible for thephosphorylation in photosynthesis were protein kinases. Finally, a total of 46 proteininteraction pairs were validated by two-hybrid experiments. Our results indicated thatone unknown protein C interacts with psaD2, a protein of photosystem I. Thus, it isquite possible that the unknown protein C is involved in photosynthesis. The databasewould facilitate us the further investigation of the chloroplast systems biology andfunctional mining of proteins related to photosynthesis in Arabidopsis thaliana.更多还原