Werneke J M, Zielinski R E, Ogren W L
Department of Plant Biology, University of Illinois, Urbana 61801.
Proc Natl Acad Sci U S A. 1988 Feb;85(3):787-91. doi: 10.1073/pnas.85.3.787.
Ribulosebisphosphate carboxylase/oxygenase activase is a recently discovered enzyme that catalyzes the activation of ribulose-1,5-bisphosphate carboxylase/oxygenase ["rubisco"; ribulose-bisphosphate carboxylase; 3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39] in vivo. Clones of rubisco activase cDNA were isolated immunologically from spinach (Spinacea oleracea L.) and Arabidopsis thaliana libraries. Sequence analysis of the spinach and Arabidopsis cDNAs identified consensus nucleotide binding sites, consistent with an ATP requirement for rubisco activase activity. A derived amino acid sequence common to chloroplast transit peptides was also identified. After synthesis of rubisco activase in vitro, the transit peptide was cleaved and the protein was transported into isolated chloroplasts. Analysis of spinach and Arabidopsis nuclear DNA by hybridization indicated a single rubisco activase gene in each species. Leaves of spinach and Arabidopsis wild type contained a single 1.9-kilobase rubisco activase mRNA. In an Arabidopsis mutant lacking rubisco activase protein, mRNA species of 1.7 and 2.1 kilobases were observed under conditions of high-stringency hybridization with a wild-type cDNA probe. This observation indicates that the lesion in the mutant arises from an error in mRNA processing.
核酮糖-1,5-二磷酸羧化酶/加氧酶激活酶是最近发现的一种酶，它在体内催化核酮糖-1,5-二磷酸羧化酶/加氧酶[“rubisco”；核酮糖二磷酸羧化酶；3-磷酸-D-甘油酸羧基裂解酶（二聚化），EC 4.1.1.39]的激活。从菠菜（Spinacea oleracea L.）和拟南芥文库中通过免疫学方法分离出rubisco激活酶cDNA克隆。对菠菜和拟南芥cDNA的序列分析确定了共有核苷酸结合位点，这与rubisco激活酶活性需要ATP一致。还鉴定出了叶绿体转运肽共有的推导氨基酸序列。在体外合成rubisco激活酶后，转运肽被切割，蛋白质被转运到分离的叶绿体中。通过杂交分析菠菜和拟南芥的核DNA表明，每个物种中都有一个rubisco激活酶基因。菠菜和拟南芥野生型叶片含有单一的1.9千碱基的rubisco激活酶mRNA。在一个缺乏rubisco激活酶蛋白的拟南芥突变体中，在与野生型cDNA探针进行高严谨度杂交的条件下，观察到了1.7和2.1千碱基的mRNA种类。这一观察结果表明，该突变体中的损伤源于mRNA加工过程中的错误。
