Energetic and structural features of SARS-CoV-2 N-protein co-assemblies with nucleic acids
Nucleocapsid (N) protein of the SARS-CoV-2 virus packages the viral genome into well-defined ribonucleoprotein particles, but the molecular pathway is still unclear. N-protein is dimeric and consists of two folded domains with nucleic acid (NA) binding sites, surrounded by intrinsically disordered r...
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Published in | iScience Vol. 24; no. 6; p. 102523 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier Inc
25.06.2021
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Nucleocapsid (N) protein of the SARS-CoV-2 virus packages the viral genome into well-defined ribonucleoprotein particles, but the molecular pathway is still unclear. N-protein is dimeric and consists of two folded domains with nucleic acid (NA) binding sites, surrounded by intrinsically disordered regions that promote liquid-liquid phase separation. Here, we use biophysical tools to study N-protein interactions with oligonucleotides of different lengths, examining the size, composition, secondary structure, and energetics of the resulting states. We observe the formation of supramolecular clusters or nuclei preceding growth into phase-separated droplets. Short hexanucleotide NA forms compact 2:2 N-protein/NA complexes with reduced disorder. Longer oligonucleotides expose additional N-protein interactions and multi-valent protein-NA interactions, which generate higher-order mixed oligomers and simultaneously promote growth of droplets. Phase separation is accompanied by a significant change in protein secondary structure, different from that caused by initial NA binding, which may contribute to the assembly of ribonucleoprotein particles within macromolecular condensates.
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•SARS-CoV-2 N-protein can oligomerize when binding short nucleic acids•Nucleic acid binding reduces disorder in N-protein•Coassembled clusters precede phase separation at high temperatures•Formation of large particles coincides with structural transitions in N-protein
Virology; Biophysics; Protein folding |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Lead contact |
ISSN: | 2589-0042 2589-0042 |
DOI: | 10.1016/j.isci.2021.102523 |