8CTK

Cryo-EM structure of SARS-CoV-2 M protein in a lipid nanodisc

Summary for 8CTK

• Entry DOI: 10.2210/pdb8ctk/pdb
• EMDB information: 26993
• Descriptor: Membrane protein (1 entity in total)
• Functional Keywords: sars-cov-2, coronavirus, viral protein, capsid protein, membrane protein
• Biological source: Severe acute respiratory syndrome coronavirus 2 (2019-nCoV, SARS-CoV-2)
• Total number of polymer chains: 2
• Total formula weight: 52381.39

Authors

Dolan, K.A.,Brohawn, S.G. (deposition date: 2022-05-15, release date: 2022-06-22, Last modification date: 2024-06-12)

Primary citation

Dolan, K.A.,Dutta, M.,Kern, D.M.,Kotecha, A.,Voth, G.A.,Brohawn, S.G.
Structure of SARS-CoV-2 M protein in lipid nanodiscs.
Elife, 11:-, 2022

PubMed Abstract: SARS-CoV-2 encodes four structural proteins incorporated into virions, spike (S), envelope (E), nucleocapsid (N), and membrane (M). M plays an essential role in viral assembly by organizing other structural proteins through physical interactions and directing them to sites of viral budding. As the most abundant protein in the viral envelope and a target of patient antibodies, M is a compelling target for vaccines and therapeutics. Still, the structure of M and molecular basis for its role in virion formation are unknown. Here, we present the cryo-EM structure of SARS-CoV-2 M in lipid nanodiscs to 3.5 Å resolution. M forms a 50 kDa homodimer that is structurally related to the SARS-CoV-2 ORF3a viroporin, suggesting a shared ancestral origin. Structural comparisons reveal how intersubunit gaps create a small, enclosed pocket in M and large open cavity in ORF3a, consistent with a structural role and ion channel activity, respectively. M displays a strikingly electropositive cytosolic surface that may be important for interactions with N, S, and viral RNA. Molecular dynamics simulations show a high degree of structural rigidity in a simple lipid bilayer and support a role for M homodimers in scaffolding viral assembly. Together, these results provide insight into roles for M in coronavirus assembly and structure.

PubMed: 36264056
DOI: 10.7554/eLife.81702

Experimental method

ELECTRON MICROSCOPY (3.52 Å)