Download MendeleyCryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss.
Bayfield, O.W., Steven, A.C., Antson, A.A.(2020) Elife 9
- PubMed: 32286226
- DOI: https://doi.org/10.7554/eLife.55517
- Primary Citation of Related Structures:
6QJT - PubMed Abstract:
The portal protein is a key component of many double-stranded DNA viruses, governing capsid assembly and genome packaging. Twelve subunits of the portal protein define a tunnel, through which DNA is translocated into the capsid. It is unknown how the portal protein functions as a gatekeeper, preventing DNA slippage, whilst allowing its passage into the capsid, and how these processes are controlled. A cryo-EM structure of the portal protein of thermostable virus P23-45, determined in situ in its procapsid-bound state, indicates a mechanism that naturally safeguards the virus against genome loss. This occurs via an inversion of the conformation of the loops that define the constriction in the central tunnel, accompanied by a hydrophilic-hydrophobic switch. The structure also shows how translocation of DNA into the capsid could be modulated by a changing mode of protein-protein interactions between portal and capsid, across a symmetry-mismatched interface.
Organizational Affiliation:
York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom.
