UMass Chan Medical School Faculty Publications

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Department of Biochemistry and Molecular Pharmacology; RNA Therapeutics Institute; Graduate School in Biomedical Sciences

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Article Preprint


Amino Acids, Peptides, and Proteins | Biochemistry | Genetic Phenomena | Structural Biology | Virology | Viruses


The capsids of double-stranded DNA viruses protect the viral genome from the harsh extracellular environment, while maintaining stability against the high internal pressure of packaged DNA. To elucidate how capsids maintain stability in an extreme environment, we used cryoelectron microscopy to determine the capsid structure of the thermostable phage P74-26. We find the P74-26 capsid exhibits an overall architecture that is very similar to those of other tailed bacteriophages, allowing us to directly compare structures to derive the structural basis for enhanced stability. Our structure reveals lasso-like interactions that appear to function like catch bonds. This architecture allows the capsid to expand during genome packaging, yet maintain structural stability. The P74-26 capsid has T=7 geometry despite being twice as large as mesophilic homologs. Capsid capacity is increased through a novel mechanism with a larger, flatter major capsid protein. Our results suggest that decreased icosahedral complexity (i.e. lower T number) leads to a more stable capsid assembly.


capsid, thermophile, stability, virus, phage, DNA viruses, viral genome, biochemistry

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The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It is made available under a CC-BY-NC 4.0 International license.

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bioRxiv 473264; doi: Link to preprint on bioRxiv service.

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Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License