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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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ResMap analysis of His-β-L HBcAg VLP reconstructions. ResMap was used to evaluate the local resolution of both T = 3 (A) and T = 4 (B) reconstructions. Isosurfaced representations of the reconstructions were coloured accordingly revealing that the HBcAg component was solved at higher resolution than the N-terminal extension. In the case of the T = 3 particle the core density achieved resolution approaching 5 Å, ranging to 8 Å in places, while the inserted polypeptide was seen to be poorer than 19 Å resolution. The T = 4 reconstruction was calculated from fewer particles and achieved lower resolution ranging between 8 and 10 Å in the HBcAg region and 11–>19 Å in the N-terminal extension. Interestingly both ResMap analyses gave resolution assessments that included small patches of poor-resolution throughout the structure, in particular within the dimeric spike of HBcAg, these are apparent in clipped isosurface representations (C and D).
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f0010: ResMap analysis of His-β-L HBcAg VLP reconstructions. ResMap was used to evaluate the local resolution of both T = 3 (A) and T = 4 (B) reconstructions. Isosurfaced representations of the reconstructions were coloured accordingly revealing that the HBcAg component was solved at higher resolution than the N-terminal extension. In the case of the T = 3 particle the core density achieved resolution approaching 5 Å, ranging to 8 Å in places, while the inserted polypeptide was seen to be poorer than 19 Å resolution. The T = 4 reconstruction was calculated from fewer particles and achieved lower resolution ranging between 8 and 10 Å in the HBcAg region and 11–>19 Å in the N-terminal extension. Interestingly both ResMap analyses gave resolution assessments that included small patches of poor-resolution throughout the structure, in particular within the dimeric spike of HBcAg, these are apparent in clipped isosurface representations (C and D).

Mentions: Resmap analysis (Kucukelbir et al., 2014) of the T = 3 reconstruction indicated a mean resolution of 7.8 Å; significantly better than the estimate derived by the FSC0.5 method. Analysis of the T = 4 structure also indicated a better resolution than that estimated by Fourier shell correlation at 0.5 cutoff, the mean resolution was determined to be 10.6 Å (Fig. 2). Local resolution measurements were seen to range between 5 and 8 Å within the core regions of the T = 3 VLP, while in the T = 4 structure the HBcAg components were resolved at between 8 and 10 Å. Interestingly in both analyses the novel density that we attribute to the N-terminal extension was highlighted as having a substantially lower resolution than the HBcAg structure. For the T = 3 particle this region was determined to have a resolution poorer than 19 Å, likewise in the T = 4 structure the trimeric spike was identified as a region of low resolution.


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)

ResMap analysis of His-β-L HBcAg VLP reconstructions. ResMap was used to evaluate the local resolution of both T = 3 (A) and T = 4 (B) reconstructions. Isosurfaced representations of the reconstructions were coloured accordingly revealing that the HBcAg component was solved at higher resolution than the N-terminal extension. In the case of the T = 3 particle the core density achieved resolution approaching 5 Å, ranging to 8 Å in places, while the inserted polypeptide was seen to be poorer than 19 Å resolution. The T = 4 reconstruction was calculated from fewer particles and achieved lower resolution ranging between 8 and 10 Å in the HBcAg region and 11–>19 Å in the N-terminal extension. Interestingly both ResMap analyses gave resolution assessments that included small patches of poor-resolution throughout the structure, in particular within the dimeric spike of HBcAg, these are apparent in clipped isosurface representations (C and D).
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4318616&req=5

f0010: ResMap analysis of His-β-L HBcAg VLP reconstructions. ResMap was used to evaluate the local resolution of both T = 3 (A) and T = 4 (B) reconstructions. Isosurfaced representations of the reconstructions were coloured accordingly revealing that the HBcAg component was solved at higher resolution than the N-terminal extension. In the case of the T = 3 particle the core density achieved resolution approaching 5 Å, ranging to 8 Å in places, while the inserted polypeptide was seen to be poorer than 19 Å resolution. The T = 4 reconstruction was calculated from fewer particles and achieved lower resolution ranging between 8 and 10 Å in the HBcAg region and 11–>19 Å in the N-terminal extension. Interestingly both ResMap analyses gave resolution assessments that included small patches of poor-resolution throughout the structure, in particular within the dimeric spike of HBcAg, these are apparent in clipped isosurface representations (C and D).
Mentions: Resmap analysis (Kucukelbir et al., 2014) of the T = 3 reconstruction indicated a mean resolution of 7.8 Å; significantly better than the estimate derived by the FSC0.5 method. Analysis of the T = 4 structure also indicated a better resolution than that estimated by Fourier shell correlation at 0.5 cutoff, the mean resolution was determined to be 10.6 Å (Fig. 2). Local resolution measurements were seen to range between 5 and 8 Å within the core regions of the T = 3 VLP, while in the T = 4 structure the HBcAg components were resolved at between 8 and 10 Å. Interestingly in both analyses the novel density that we attribute to the N-terminal extension was highlighted as having a substantially lower resolution than the HBcAg structure. For the T = 3 particle this region was determined to have a resolution poorer than 19 Å, likewise in the T = 4 structure the trimeric spike was identified as a region of low resolution.

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