6QJT image
Deposition Date 2019-01-24
Release Date 2020-03-25
Last Version Date 2024-05-15
Entry Detail
PDB ID:
6QJT
Keywords:
Title:
Thermophage P23-45 in situ procapsid portal protein
Biological Source:
Source Organism:
Method Details:
Experimental Method:
Resolution:
3.74 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Portal protein
Gene (Uniprot):P23p86
Chain IDs:A
Chain Length:448
Number of Molecules:1
Biological Source:Thermus virus P23-45
Ligand Molecules
Primary Citation
Cryo-EM structure in situ reveals a molecular switch that safeguards virus against genome loss.
Elife 9 ? ? (2020)
PMID: 32286226 DOI: 10.7554/eLife.55517

Abstact

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.

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Primary Citation of related structures