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| Main Authors: | , , , , , , , , , , , , |
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| Format: | Artículo científico |
| Language: | en |
| Published: |
Plant physiology
2024
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| Subjects: | |
| Online Access: | https://pubmed.ncbi.nlm.nih.gov/39680612/ |
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Table of Contents:
- Rubisco packaging and stoichiometric composition of the native β-carboxysome in Synechococcus elongatus PCC7942. Sun, Yaqi Sheng, Yuewen Ni, Tao Ge, Xingwu Sarsby, Joscelyn Brownridge, Philip J Li, Kang Hardenbrook, Nathan Dykes, Gregory F Rockliffe, Nichola Eyers, Claire E Zhang, Peijun Liu, Lu-Ning Synechococcus Ribulose-Bisphosphate Carboxylase Bacterial Proteins Organelles Carbon Dioxide Cryoelectron Microscopy 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.