Rubisco packaging and stoichiometric composition of the native β-carboxysome in <i>Synechococcus elongatus</i> PCC7942
Carboxysomes are anabolic bacterial microcompartments that play an essential role in CO2 fixation in cyanobacteria. This self-assembling proteinaceous organelle uses a polyhedral shell constructed by hundreds of shell protein paralogs to encapsulate the key CO2-fixing enzymes Rubisco and carbonic anhydrase. Deciphering the precise arrangement and structural organization of Rubisco enzymes within carboxysomes is crucial for understanding carboxysome formation and overall functionality. Here, we employed cryoelectron tomography and subtomogram averaging to delineate the 3D packaging of Rubiscos within β-carboxysomes in the freshwater cyanobacterium Synechococcus elongatus PCC7942 grown under low light. Our results revealed that Rubiscos are arranged in multiple concentric layers parallel to the shell within the β-carboxysome lumen. We also detected Rubisco binding with the scaffolding protein CcmM in β-carboxysomes, which is instrumental for Rubisco encapsulation and β-carboxysome assembly. Using Quantification conCATamer-based quantitative MS, we determined the absolute stoichiometric composition of the entire β-carboxysome. This study provides insights into the assembly principles and structural variation of β-carboxysomes, which will aid in the rational design and repurposing of carboxysome nanostructures for diverse bioengineering applications.
Authors
- Yaqi Sun (ORCID: https://orcid.org/0000-0002-2175-7905)
- Tao Ni (ORCID: https://orcid.org/0000-0001-7268-0306)
- Claire E. Eyers (ORCID: https://orcid.org/0000-0002-3223-5926)
- Lu‐Ning Liu (ORCID: https://orcid.org/0000-0002-8884-4819)
- Joscelyn Sarsby (ORCID: https://orcid.org/0000-0002-1942-6306)
- Philip Brownridge (ORCID: https://orcid.org/0000-0003-0105-6594)
- Gregory F. Dykes (ORCID: https://orcid.org/0000-0002-0626-9487)
- Yuewen Sheng (ORCID: https://orcid.org/0000-0003-3067-9520)
- Kang Li (ORCID: https://orcid.org/0000-0002-9141-860X)
- Peijun Zhang (ORCID: https://orcid.org/0000-0003-1803-691X)
- Xingwu Ge (ORCID: https://orcid.org/0009-0009-9499-8978)
- Nichola Rockliffe
- Nathan Hardenbrook
Institutions
- Centre for Human Genetics (GB)
- University of Liverpool (GB)
- Chinese Academy of Medical Sciences & Peking Union Medical College (CN)
- Diamond Light Source (GB)
- University of Oxford (GB)
- Systems Biology Institute (JP)
- Science Oxford (GB)
- Ocean University of China (CN)
Publication Details
- Journal
- PLANT PHYSIOLOGY
- Published
- 2024-12-16
- DOI
- https://doi.org/10.1093/plphys/kiae665
- Citations
- 12
- Primary Topic
- Photosynthetic Processes and Mechanisms
- Type
- article
- Field-Weighted Citation Impact
- 2.81
Funders
- Wellcome Trust
- Diamond Light Source
- National Institute for Health and Care Research
- Leverhulme Trust
- Royal Society
- National Natural Science Foundation of China
- National Institutes of Health
- Directorate for Biological Sciences
- Musculoskeletal Research Center, Washington University in St. Louis
- Medical Research Council
- Biotechnology and Biological Sciences Research Council
- Natural Environment Research Council
- National Key Research and Development Program of China
- Biomedical Research Council
- NIHR Oxford Biomedical Research Centre