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Title | Single-particle cryo-EM analysis of the shell architecture and internal organization of an intact α-carboxysome. |
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Journal, issue, pages | Structure, Vol. 31, Issue 6, Page 677-688.e4, Year 2023 |
Publish date | Jun 1, 2023 |
Authors | Sasha L Evans / Monsour M J Al-Hazeem / Daniel Mann / Nicolas Smetacek / Andrew J Beavil / Yaqi Sun / Taiyu Chen / Gregory F Dykes / Lu-Ning Liu / Julien R C Bergeron / |
PubMed Abstract | Carboxysomes are proteinaceous bacterial microcompartments that sequester the key enzymes for carbon fixation in cyanobacteria and some proteobacteria. They consist of a virus-like icosahedral shell, ...Carboxysomes are proteinaceous bacterial microcompartments that sequester the key enzymes for carbon fixation in cyanobacteria and some proteobacteria. They consist of a virus-like icosahedral shell, encapsulating several enzymes, including ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO), responsible for the first step of the Calvin-Benson-Bassham cycle. Despite their significance in carbon fixation and great bioengineering potentials, the structural understanding of native carboxysomes is currently limited to low-resolution studies. Here, we report the characterization of a native α-carboxysome from a marine cyanobacterium by single-particle cryoelectron microscopy (cryo-EM). We have determined the structure of its RuBisCO enzyme, and obtained low-resolution maps of its icosahedral shell, and of its concentric interior organization. Using integrative modeling approaches, we have proposed a complete atomic model of an intact carboxysome, providing insight into its organization and assembly. This is critical for a better understanding of the carbon fixation mechanism and toward repurposing carboxysomes in synthetic biology for biotechnological applications. |
External links | Structure / PubMed:37015227 / PubMed Central |
Methods | EM (single particle) / EM (tomography) |
Resolution | 2.87 - 20.0 Å |
Structure data | EMDB-14376: Cryo-EM structure of the Cyanobium sp. PCC 7001 RuBisCO enzyme at 3.8 A resolution with C1 symmetry EMDB-14377: Cryo-EM structure of Cyanobium sp. PCC 7001 carboxysome shell EMDB-14379: Cryo-EM structure of an intact carboxysome - core layer EMDB-14380: Cryo-EM structure of the Cyanobium sp. PCC 7001 Carboxysome internal density outer layer EMDB-14381: Cryo-EM structure of the Cyanobium sp. PCC 7001 Carboxysome internal density middle layer EMDB-14385, PDB-7yyo: EMDB-50580: SOLIST cryo-tomogram of native left ventricle mouse heart muscle #1 EMDB-50582: SOLIST native mouse heart muscle tomogram #2 PDB-8cmy: |
Chemicals | ChemComp-MG: ChemComp-CAP: |
Source |
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Keywords | PHOTOSYNTHESIS / Carboxysome / carbon fixation / cyanobacteria |