摘要
Abstract
The fixation of carbon in plants is a crucial step in the carbon cycle,significantly impacting global food production and climate change.Within this process,the ribulose-1,5-bisphosphate carboxylase enzyme plays a pivotal role.There exists a delicate balance between the enzyme's catalytic rate and its specificity:as the specificity decreases,the catalytic rate rises,but this is accompanied by an increase in toxic by-products from side reactions,ultimately affecting overall efficiency.However,aquatic plants possess a unique mechanism for carbon dioxide enrichment,effectively minimizing the impact of side reactions and creating a more favorable environment for the enzyme.Using the submergence events of higher aquatic plants as a starting point,we comprehensively studied the convergent evolution of the large subunit protein of ribulose-1,5-bisphosphate carboxylase(RuBisCO)in these plants.Our aim was to identify convergent evolutionary sites related to submergence events and explore changes in the enzyme's physicochemical properties following the emergence of the carbon dioxide enrichment mechanism,providing new insights for optimizing the enzyme.We collected protein sequence information for ribulose-1,5-bisphosphate carboxylase from 48 species belonging to six orders:Alismatales,Lamiales,Saxifragales,Hydrocharitales,Cornales,and Ceratophyllales,and identified six submergence events.Employing the PCOC analysis method,we integrated data from these six submergence events to investigate common evolutionary trends in aquatic plants.Our analysis revealed the potential existence of a convergent evolutionary site in aquatic plants,located at position 328 in the protein sequence,adjacent to the enzyme's active center.We hypothesize that substitutions at this site may enhance the flexibility of controlling the entry of reaction substrates into the active center,thereby facilitating the entry of carbon dioxide and increasing the enzyme's catalytic rate.The discovery of this convergent evolutionary site provides a research direction and theoretical basis for subsequent enzyme improvement and mutation experiments.Our findings will contribute to further optimizing the catalytic efficiency and adaptability of this enzyme.关键词
核酮糖-1,5-二磷酸羧化酶/高等水生植物入水事件/CO2富集机制/趋同进化Key words
ribulose-1,5-bisphosphate carboxylase/submergence events of higher aquatic plants/carbon dioxide enrichment mechanism/convergent evolution分类
生物科学
