Inactivation of the conserved open reading frame ycf34 of Synechocystis sp
Inactivation of the conserved open reading frame ycf34 of Synechocystis sp
复制标题
集胞藻保守开放阅读框 ycf34 的失活
DOI：
10.1016/j.bbabio.2012.06.002
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Nicole Frankenberg,. Dinkel and Annegret Wilde
中科院分区：
文献类型：
--
作者：
Thomas Wallner;Yoshinori Hagiwara;Gabor Bernat;Roman Sobotka;Edward J. Reijerse;Nicole Frankenberg,. Dinkel and Annegret Wilde
Ycf 34是一个假设的叶绿体开放阅读框架，存在于几种非绿藻的叶绿体基因组中。Ycf 34同源物也编码在蓝藻的所有测序基因组中。为了评估Ycf 34的作用，我们构建并分析了蓝藻突变株。集胞藻PCC 6803中ycf 34的失活在正常光照生长条件下没有表现出明显的表型。然而，当细胞在低光强度下生长时，它们含有更少和更小的藻胆体触角，并显示出强烈的生长迟缓，这表明Ycf 34多肽在光限制条件下的重要作用。北方印迹分析显示，与野生型和正常光照条件相比，在光限制生长下ycf 34突变体中藻蓝蛋白操纵子的表达非常弱。氧释放和P700测量表明受损的电子流之间的光系统II和光系统I在这些条件下，这表明受损的天线的大小是最有可能由于一个高度减少质体醌池，触发在转录水平上的调节。使用FLAG标记的Ycf 34，我们发现，这种蛋白质是紧密结合的类囊体膜。重组Ycf 34蛋白的紫外-可见光谱和穆斯堡尔谱表明存在铁-硫簇。由于Ycf 34缺乏同源性，已知的铁-硫簇含有蛋白质，它可能构成一种新型的铁-硫蛋白参与氧化还原信号或优化光合电子传递链。
Ycf34 is a hypothetical chloroplast open reading frame that is present in the chloroplast genomes of several non-green algae. Ycf34 homologues are also encoded in all sequenced genomes of cyanobacteria. To evaluate the role of Ycf34 we have constructed and analysed a cyanobacterial mutant strain. Inactivation of ycf34 in Synechocystis sp. PCC 6803 showed no obvious phenotype under normal light intensity growth conditions. However, when the cells were grown under low light intensity they contained less and smaller phycobilisome antennae and showed a strongly retarded growth, suggesting an essential role of the Ycf34 polypeptide under light limiting conditions. Northern blot analysis revealed a very weak expression of the phycocyanin operon in the ycf34 mutant under light limiting growth in contrast to the wild type and to normal light conditions. Oxygen evolution and P700measurements showed impaired electron flow between photosystem II and photosystem I under these conditions which suggest that the impaired antenna size is most likely due to a highly reduced plastoquinone pool which triggers regulation on a transcriptional level. Using a FLAG-tagged Ycf34 we found that this protein is tightly bound to the thylakoid membranes. UV–vis and Mössbauer spectroscopy of the recombinant Ycf34 protein demonstrate the presence of an iron–sulphur cluster. Since Ycf34 lacks homology to known iron–sulphur cluster containing proteins, it might constitute a new type of iron–sulphur protein implicated in redox signalling or in optimising the photosynthetic electron transport chain.