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An N-terminal extension to the hepatitis B virus core protein forms a poorly ordered trimeric spike in assembled virus-like particles.

McGonigle R, Yap WB, Ong ST, Gatherer D, Bakker SE, Tan WS, Bhella D - J. Struct. Biol. (2014)

Bottom Line: Virus-like particles composed of the core antigen of hepatitis B virus (HBcAg) have been shown to be an effective platform for the display of foreign epitopes in vaccine development.Heterologous sequences have been successfully inserted at both amino and carboxy termini as well as internally at the major immunodominant epitope.We hypothesise that the capacity of N-terminal inserts to form trimers may have application in the development of multivalent vaccines to trimeric antigens.

View Article: PubMed Central - PubMed

Affiliation: MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK.

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3D reconstructions of His-β-L HBcAg virus-like particles. (A) Cryomicroscopy of His-β-L HBcAg VLPs revealed two sizes 30 nm T = 3 and 34 nm T = 4. (B) The T = 3 structure was generated using 6048 particle images and achieved a resolution of 10 Å. (C) The T = 4 VLP was reconstructed using 2040 particles and achieved a resolution of 12 Å. Resolution assessment was by the FSC0.5 criterion (D). The general architecture of both capsids is similar to the wild type HBcAg, as demonstrated by comparison with a solvent exclusion surface representation of the T = 4 capsid calculated from the X-ray structure PDB ID 1QGT (E). His-β-L HBcAg particles however were seen to bear an extra spike density hypothesised to comprise a trimer of the extended N-terminus, located at sites of local threefold symmetry in the T = 3 VLP (magenta) and at both icosahedral (green) and local (magenta) threefold symmetry axes in the T = 4 particle. Wall-eyed stereo pair images are presented (B, C and E). Cross-sections through the T = 3 (F) and T = 4 (G) reconstructions show that the density in the N-terminal spikes is blurred compared to that of the HBcAg component (magenta and green arrows).
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f0005: 3D reconstructions of His-β-L HBcAg virus-like particles. (A) Cryomicroscopy of His-β-L HBcAg VLPs revealed two sizes 30 nm T = 3 and 34 nm T = 4. (B) The T = 3 structure was generated using 6048 particle images and achieved a resolution of 10 Å. (C) The T = 4 VLP was reconstructed using 2040 particles and achieved a resolution of 12 Å. Resolution assessment was by the FSC0.5 criterion (D). The general architecture of both capsids is similar to the wild type HBcAg, as demonstrated by comparison with a solvent exclusion surface representation of the T = 4 capsid calculated from the X-ray structure PDB ID 1QGT (E). His-β-L HBcAg particles however were seen to bear an extra spike density hypothesised to comprise a trimer of the extended N-terminus, located at sites of local threefold symmetry in the T = 3 VLP (magenta) and at both icosahedral (green) and local (magenta) threefold symmetry axes in the T = 4 particle. Wall-eyed stereo pair images are presented (B, C and E). Cross-sections through the T = 3 (F) and T = 4 (G) reconstructions show that the density in the N-terminal spikes is blurred compared to that of the HBcAg component (magenta and green arrows).

Mentions: Cryomicrographs of purified His-β-L HBcAg VLPs showed the presence of two populations of differently sized particles with diameters of approximately 30 nm and 34 nm, corresponding to the expected sizes for T = 3 and T = 4 classes (Fig. 1A). The T = 3 form was most common (74.4%), in line with the findings of previous studies showing that truncation of the C-terminus increases the ratio of T = 3 versus T = 4 particles (Pumpens and Grens, 2001). 7046 T = 3 and 2419 T = 4 particles were extracted from 785 micrographs and processed to calculate three-dimensional reconstructions.


An N-terminal extension to the hepatitis B virus core protein forms a poorly ordered trimeric spike in assembled virus-like particles.

McGonigle R, Yap WB, Ong ST, Gatherer D, Bakker SE, Tan WS, Bhella D - J. Struct. Biol. (2014)

3D reconstructions of His-β-L HBcAg virus-like particles. (A) Cryomicroscopy of His-β-L HBcAg VLPs revealed two sizes 30 nm T = 3 and 34 nm T = 4. (B) The T = 3 structure was generated using 6048 particle images and achieved a resolution of 10 Å. (C) The T = 4 VLP was reconstructed using 2040 particles and achieved a resolution of 12 Å. Resolution assessment was by the FSC0.5 criterion (D). The general architecture of both capsids is similar to the wild type HBcAg, as demonstrated by comparison with a solvent exclusion surface representation of the T = 4 capsid calculated from the X-ray structure PDB ID 1QGT (E). His-β-L HBcAg particles however were seen to bear an extra spike density hypothesised to comprise a trimer of the extended N-terminus, located at sites of local threefold symmetry in the T = 3 VLP (magenta) and at both icosahedral (green) and local (magenta) threefold symmetry axes in the T = 4 particle. Wall-eyed stereo pair images are presented (B, C and E). Cross-sections through the T = 3 (F) and T = 4 (G) reconstructions show that the density in the N-terminal spikes is blurred compared to that of the HBcAg component (magenta and green arrows).
© Copyright Policy - CC BY
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4318616&req=5

f0005: 3D reconstructions of His-β-L HBcAg virus-like particles. (A) Cryomicroscopy of His-β-L HBcAg VLPs revealed two sizes 30 nm T = 3 and 34 nm T = 4. (B) The T = 3 structure was generated using 6048 particle images and achieved a resolution of 10 Å. (C) The T = 4 VLP was reconstructed using 2040 particles and achieved a resolution of 12 Å. Resolution assessment was by the FSC0.5 criterion (D). The general architecture of both capsids is similar to the wild type HBcAg, as demonstrated by comparison with a solvent exclusion surface representation of the T = 4 capsid calculated from the X-ray structure PDB ID 1QGT (E). His-β-L HBcAg particles however were seen to bear an extra spike density hypothesised to comprise a trimer of the extended N-terminus, located at sites of local threefold symmetry in the T = 3 VLP (magenta) and at both icosahedral (green) and local (magenta) threefold symmetry axes in the T = 4 particle. Wall-eyed stereo pair images are presented (B, C and E). Cross-sections through the T = 3 (F) and T = 4 (G) reconstructions show that the density in the N-terminal spikes is blurred compared to that of the HBcAg component (magenta and green arrows).
Mentions: Cryomicrographs of purified His-β-L HBcAg VLPs showed the presence of two populations of differently sized particles with diameters of approximately 30 nm and 34 nm, corresponding to the expected sizes for T = 3 and T = 4 classes (Fig. 1A). The T = 3 form was most common (74.4%), in line with the findings of previous studies showing that truncation of the C-terminus increases the ratio of T = 3 versus T = 4 particles (Pumpens and Grens, 2001). 7046 T = 3 and 2419 T = 4 particles were extracted from 785 micrographs and processed to calculate three-dimensional reconstructions.

Bottom Line: Virus-like particles composed of the core antigen of hepatitis B virus (HBcAg) have been shown to be an effective platform for the display of foreign epitopes in vaccine development.Heterologous sequences have been successfully inserted at both amino and carboxy termini as well as internally at the major immunodominant epitope.We hypothesise that the capacity of N-terminal inserts to form trimers may have application in the development of multivalent vaccines to trimeric antigens.

View Article: PubMed Central - PubMed

Affiliation: MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK.

Show MeSH
Related in: MedlinePlus