Structure and assembly of cargo Rubisco in two native α-carboxysomes

Journal article

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

Authors: Ni, T; Sun, Y; Burn, W; Al-Hazeem, MMJ; Zhu, Y

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature Communications
• Volume: 13
• Issue: 1
• Pages: 4299-4299
• Article number: 4299
• Publication date: 2022-07-25
• DOI: 10.1038/s41467-022-32004-w
• EISSN: 2041-1723
• ISSN: 2041-1723
• Language: English
• Keywords: Enzyme; Pyruvate carboxylase; Biophysics; Physics; Carbon fixation; Paleontology; Chemistry; Cryo-electron tomography; Cyanobacteria; RuBisCO; Bacteria; Biology; Biochemistry; Photosynthesis