Torrado Alejandro, Iniesta-Pallarés Macarena, Velázquez-Campoy Adrián, Álvarez Consolación, Mariscal Vicente, Molina-Heredia Fernando P
Instituto de Bioquímica Vegetal y Fotosíntesis (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas), Sevilla, Spain.
Institute of Biocomputation and Complex Systems Physics, Universidad de Zaragoza, Zaragoza, Spain.
Front Plant Sci. 2023 Sep 6;14:1227492. doi: 10.3389/fpls.2023.1227492. eCollection 2023.
All known photosynthetic cyanobacteria carry a cytochrome protein that acts transferring electrons from cytochrome complex to photosystem I, in photosynthesis, or cytochrome oxidase, in respiration. In most of the cyanobacteria, at least one homologue to cytochrome is found, the so-called cytochrome or cytochrome . However, the function of these cytochrome -like proteins is still unknown. Recently, it has been proposed a common origin of these proteins as well as the reclassification of the cytochrome group as , renaming the new joint group as cytochrome . Another homologue to cytochrome has not been classified yet, the formerly called cytochrome , which is present in the heterocyst-forming filamentous cyanobacteria sp. PCC 7119. In this work, we propose the inclusion of this group as an independent group in the genealogy of cytochrome -like proteins with significant differences from cytochrome and cytochrome , with the proposed name cytochrome . To support this proposal, new data about phylogeny, genome localisation and functional properties of cytochrome -like proteins is provided. Also, we have analysed the interaction of cytochrome -like proteins with cytochrome by isothermal titration calorimetry and by molecular docking, concluding that -like proteins could interact with cytochrome complex in a similar fashion as cytochrome . Finally, we have analysed the reactivity of cytochrome -like proteins with membranes enriched in terminal oxidases of cyanobacteria by oxygen uptake experiments, concluding that cytochrome is able to react with the specific copper-oxidase of the heterocysts, the cytochrome oxidase 2.
所有已知的光合蓝细菌都携带一种细胞色素蛋白，该蛋白在光合作用中负责将电子从细胞色素复合物传递到光系统I，或在呼吸作用中传递到细胞色素氧化酶。在大多数蓝细菌中，至少能找到一种与细胞色素 同源的蛋白，即所谓的细胞色素 或细胞色素 。然而，这些类细胞色素蛋白的功能仍然未知。最近，有人提出这些蛋白有共同的起源，并将细胞色素 组重新分类为 ，将新的联合组命名为细胞色素 。另一种与细胞色素 同源的蛋白尚未分类，即以前称为细胞色素 的蛋白，它存在于形成异形胞的丝状蓝细菌 sp. PCC 7119中。在这项工作中，我们建议将这个组作为一个独立的组纳入类细胞色素蛋白的谱系中，它与细胞色素 和细胞色素 有显著差异，建议命名为细胞色素 。为支持这一建议，我们提供了有关类细胞色素蛋白的系统发育、基因组定位和功能特性的新数据。此外，我们通过等温滴定量热法和分子对接分析了类细胞色素蛋白与细胞色素 的相互作用，得出结论：类 蛋白可以与细胞色素 复合物以与细胞色素 相似的方式相互作用。最后，我们通过氧摄取实验分析了类细胞色素蛋白与富含蓝细菌末端氧化酶的膜的反应性，得出结论：细胞色素 能够与异形胞的特异性铜氧化酶，即细胞色素 氧化酶2发生反应。
