Journal: ACS Nano / Year: 2025 Title: Synthetic Rewiring of Virus-like Particles via Circular Permutation Enables Modular Peptide Display and Protein Encapsulation. Authors: Shiqi Liang / Kaavya Butaney / Daniel de Castro Assumpção / James Jung / Nolan W Kennedy / Danielle Tullman-Ercek / Abstract: Virus-like particles (VLPs) are self-assembling nanoparticles derived from viruses with the potential as scaffolds for myriad applications. They are also excellent testbeds for engineering protein ...Virus-like particles (VLPs) are self-assembling nanoparticles derived from viruses with the potential as scaffolds for myriad applications. They are also excellent testbeds for engineering protein superstructures. Engineers often employ techniques such as amino acid substitutions and insertions/deletions. Yet evolution also utilizes circular permutation, a powerful natural strategy that has not been fully explored in engineering self-assembling protein nanoparticles. Here, we demonstrate this technique using the MS2 VLP as a model self-assembling proteinaceous nanoparticle. We constructed a comprehensive circular permutation library of the fused MS2 coat protein dimer construct. The strategy revealed terminal locations, validated via cryo-electron microscopy, that enabled C-terminal peptide tagging and led to a protein encapsulation strategy via covalent bonding - a feature the native coat protein does not permit. Our systematic study demonstrates the power of circular permutation for engineering features as well as quantitatively and systematically exploring VLP structural determinants.
History
Deposition
May 2, 2025
Deposition site: RCSB / Processing site: RCSB
Revision 1.0
Nov 5, 2025
Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: EM metadata / Data content type: EM metadata / Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: FSC / Data content type: FSC / Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: Half map / Part number: 1 / Data content type: Half map / Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: Half map / Part number: 2 / Data content type: Half map / Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: Image / Data content type: Image / Provider: repository / Type: Initial release
Revision 1.0
Nov 5, 2025
Data content type: Primary map / Data content type: Primary map / Provider: repository / Type: Initial release
Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 95 % / Chamber temperature: 288 K
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Electron microscopy imaging
Microscopy
Model: TFS GLACIOS
Electron gun
Electron source: FIELD EMISSION GUN / Accelerating voltage: 200 kV / Illumination mode: FLOOD BEAM
Electron lens
Mode: BRIGHT FIELD / Nominal magnification: 130000 X / Nominal defocus max: 1600 nm / Nominal defocus min: 600 nm / Cs: 2.7 mm / C2 aperture diameter: 20 µm / Alignment procedure: COMA FREE
Specimen holder
Cryogen: NITROGEN / Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Temperature (min): 77 K
Image recording
Average exposure time: 5.33 sec. / Electron dose: 60 e/Å2 / Film or detector model: TFS FALCON 4i (4k x 4k) / Num. of grids imaged: 1 / Num. of real images: 5849
EM imaging optics
Energyfilter name: TFS Selectris / Energyfilter slit width: 10 eV
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Processing
EM software
ID
Name
Version
Category
1
cryoSPARC
4.6.2
particleselection
2
EPU
3.9.1
imageacquisition
4
cryoSPARC
4.6.2
CTFcorrection
7
Coot
modelfitting
9
cryoSPARC
4.6.2
initialEulerassignment
10
cryoSPARC
4.6.2
finalEulerassignment
11
cryoSPARC
4.6.2
classification
12
cryoSPARC
4.6.2
3Dreconstruction
13
PHENIX
1.21.2
modelrefinement
CTF correction
Type: PHASE FLIPPING AND AMPLITUDE CORRECTION
Particle selection
Num. of particles selected: 539975
Symmetry
Point symmetry: I (icosahedral)
3D reconstruction
Resolution: 2.62 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 109941 / Algorithm: BACK PROJECTION / Num. of class averages: 1 / Symmetry type: POINT
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