Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
Science. 2022 Oct 14;378(6616):155-160. doi: 10.1126/science.abq1416. Epub 2022 Oct 13.
The evolution of ribulose-1,5-bisphosphate carboxylase/oxygenases (Rubiscos) that discriminate strongly between their substrate carbon dioxide and the undesired side substrate dioxygen was an important event for photosynthetic organisms adapting to an oxygenated environment. We use ancestral sequence reconstruction to recapitulate this event. We show that Rubisco increased its specificity and carboxylation efficiency through the gain of an accessory subunit before atmospheric oxygen was present. Using structural and biochemical approaches, we retrace how this subunit was gained and became essential. Our work illuminates the emergence of an adaptation to rising ambient oxygen levels, provides a template for investigating the function of interactions that have remained elusive because of their essentiality, and sheds light on the determinants of specificity in Rubisco.
核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubiscos）的进化对于适应富氧环境的光合生物来说是一个重要事件，因为它能够强烈区分其底物二氧化碳和不需要的侧底物氧气。我们使用祖先序列重建来重现这一事件。我们表明，Rubisco 在大气氧存在之前通过获得辅助亚基来提高其特异性和羧化效率。我们使用结构和生化方法追溯了这个亚基是如何获得并变得必不可少的。我们的工作阐明了对不断上升的环境氧气水平的适应的出现，为研究由于其必需性而一直难以捉摸的相互作用的功能提供了模板，并揭示了 Rubisco 特异性的决定因素。
