Photosynthetic electron transfer occurs efficiently in specialized internal membranes known as thylakoid membranes.Thylakoid membranes exhibit diverse structural variations across photoautotrophic organisms.We studied...Photosynthetic electron transfer occurs efficiently in specialized internal membranes known as thylakoid membranes.Thylakoid membranes exhibit diverse structural variations across photoautotrophic organisms.We studied how a key protein,CurT,shapes thylakoid membranes of a model cyanobacterium Synechococcus elongatus PCC 7942(Syn7942),a rod-shaped cyanobacterium with regular concentric thylakoid layers.By guiding the curves and structure of thylakoid membranes,CurT helps the cells capture light efficiently,especially when conditions change.The detailed characterization of the role of CurT in Syn7942 offers new clues about how nature builds high-performance photosynthetic membrane systems in response to environmental fluctuations.These findings may inspire future ways to redesign photosynthetic membranes for better crop yields or cleaner bioenergy production.展开更多
Rubisco(ribulose-1,5-bisphosphate carboxylase/oxygenase)is the central enzyme for conversion of atmospheric CO_(2)into organic molecules,playing a crucial role in the global carbon cycle.In cyanobacteria and some chem...Rubisco(ribulose-1,5-bisphosphate carboxylase/oxygenase)is the central enzyme for conversion of atmospheric CO_(2)into organic molecules,playing a crucial role in the global carbon cycle.In cyanobacteria and some chemoautotrophs,Rubisco complexes,together with carbonic anhydrase,are enclosed within specific proteinaceous microcompartments known as carboxysomes.The polyhedral carboxysome shell ensures the dense packaging of Rubisco and creates a high-CO_(2)internal environment to facilitate CO_(2)fixation.Rubisco and carboxysomes have been popular targets for bioengineering,with the intent of enhancing plant photosynthesis,crop yields,and biofuel production.However,efficient generation of Form 1B Rubisco and cyanobacterial b-carboxysomes in heterologous systems remains a challenge.Here,we developed genetic systems to efficiently engineer functional cyanobacterial Form 1B Rubisco in Escherichia coli by incorporating Rubisco assembly factor Raf1 and modulating the RbcL/S stoichiometry.We then reconstituted catalytically active b-carboxysomes in E.coli with cognate Form 1B Rubisco by fine-tuning the expression levels of individual b-carboxysome components.In addition,we investigated the mechanism of Rubisco encapsulation into carboxysomes by constructing hybrid carboxysomes;this was achieved by creating a chimeric encapsulation peptide incorporating small sub-unit-like domains,which enabled the encapsulation of Form 1B Rubisco into a-carboxysome shells.Our study provides insights into the assembly mechanisms of plant-like Form 1B Rubisco and the principles of its encapsulation in both b-carboxysomes and hybrid carboxysomes,highlighting the inherent modularity of carboxysome structures.These findings lay the framework for rational design and repurposing of CO_(2)-fixing modules in bioengineering applications,e.g.,crop engineering,biocatalyst production,and molecule delivery.展开更多
基金supported by the National Key R&D Program of China(2021YFA0909600 and 2023YFA0914600)the National Natural Science Foundation of China(32070109)+1 种基金the Biotechnology and Biological Sciences Research Council(BB/V009729/1,BB/Y01135X/1,and BB/Y008308/1)the Royal Society(URF\R\180030).
文摘Photosynthetic electron transfer occurs efficiently in specialized internal membranes known as thylakoid membranes.Thylakoid membranes exhibit diverse structural variations across photoautotrophic organisms.We studied how a key protein,CurT,shapes thylakoid membranes of a model cyanobacterium Synechococcus elongatus PCC 7942(Syn7942),a rod-shaped cyanobacterium with regular concentric thylakoid layers.By guiding the curves and structure of thylakoid membranes,CurT helps the cells capture light efficiently,especially when conditions change.The detailed characterization of the role of CurT in Syn7942 offers new clues about how nature builds high-performance photosynthetic membrane systems in response to environmental fluctuations.These findings may inspire future ways to redesign photosynthetic membranes for better crop yields or cleaner bioenergy production.
基金supported by the National Key R&D Program of China(2023YFA0914600 and 2021YFA0909600)the National Natural Science Foundation of China(32070109)+5 种基金Biotechnology and Biological Sciences Research Council Grants(BB/Y01135X/1,BB/V009729/1,BB/Y008308/1,and BB/S003339/1)the Leverhulme Trust(RPG-2021-286 and RPG-2019-300)the Natural Environment Research Council Grant(NE/Z00019X/1)the Royal Society(URF\R\180030 and RGF\EA\181061),the ERC Advanced Grant(101021133)the Wellcome Trust Investigator Award(206422/Z/17/Z).support of the cryo-EM facilities at the UK National electron Bio-Imaging Centre(eBIC),proposal NT21004.
文摘Rubisco(ribulose-1,5-bisphosphate carboxylase/oxygenase)is the central enzyme for conversion of atmospheric CO_(2)into organic molecules,playing a crucial role in the global carbon cycle.In cyanobacteria and some chemoautotrophs,Rubisco complexes,together with carbonic anhydrase,are enclosed within specific proteinaceous microcompartments known as carboxysomes.The polyhedral carboxysome shell ensures the dense packaging of Rubisco and creates a high-CO_(2)internal environment to facilitate CO_(2)fixation.Rubisco and carboxysomes have been popular targets for bioengineering,with the intent of enhancing plant photosynthesis,crop yields,and biofuel production.However,efficient generation of Form 1B Rubisco and cyanobacterial b-carboxysomes in heterologous systems remains a challenge.Here,we developed genetic systems to efficiently engineer functional cyanobacterial Form 1B Rubisco in Escherichia coli by incorporating Rubisco assembly factor Raf1 and modulating the RbcL/S stoichiometry.We then reconstituted catalytically active b-carboxysomes in E.coli with cognate Form 1B Rubisco by fine-tuning the expression levels of individual b-carboxysome components.In addition,we investigated the mechanism of Rubisco encapsulation into carboxysomes by constructing hybrid carboxysomes;this was achieved by creating a chimeric encapsulation peptide incorporating small sub-unit-like domains,which enabled the encapsulation of Form 1B Rubisco into a-carboxysome shells.Our study provides insights into the assembly mechanisms of plant-like Form 1B Rubisco and the principles of its encapsulation in both b-carboxysomes and hybrid carboxysomes,highlighting the inherent modularity of carboxysome structures.These findings lay the framework for rational design and repurposing of CO_(2)-fixing modules in bioengineering applications,e.g.,crop engineering,biocatalyst production,and molecule delivery.
