9FWV

Rubisco in native beta-carboxysomes

Summary for 9FWV

• Entry DOI: 10.2210/pdb9fwv/pdb
• EMDB information: 50836
• Descriptor: Carboxysome assembly protein CcmM, Ribulose bisphosphate carboxylase large chain, Ribulose bisphosphate carboxylase small subunit (3 entities in total)
• Functional Keywords: rubisco, ccmm, photosynthesis
• Biological source: Synechococcus elongatus PCC 7942 = FACHB-805; More
• Total number of polymer chains: 20
• Total formula weight: 529634.96

Authors

Sheng, Y.,Hardenbrook, N.,Li, K. (deposition date: 2024-07-01, release date: 2025-05-07, Last modification date: 2025-07-02)

Primary citation

Sun, Y.,Sheng, Y.,Ni, T.,Ge, X.,Sarsby, J.,Brownridge, P.J.,Li, K.,Hardenbrook, N.,Dykes, G.F.,Rockliffe, N.,Eyers, C.E.,Zhang, P.,Liu, L.N.
Rubisco packaging and stoichiometric composition of the native beta-carboxysome in Synechococcus elongatus PCC7942.
Plant Physiol., 197:-, 2024

PubMed Abstract: 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.

PubMed: 39680612
DOI: 10.1093/plphys/kiae665

Experimental method

ELECTRON MICROSCOPY (3.5 Å)