The Structural Biology of Hepatitis B Virus: Form and Function

Venkatakrishnan, Balasubramanian; Zlotnick, Adam

doi:10.1146/annurev-virology-110615-042238

Cited by 132 publications

(144 citation statements)

References 178 publications

(246 reference statements)

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“…Single particle analysis revealed that, in these conditions, MS2 phage could assemble its capsid in both T = 3 and T = 4 icosahedral settings, as well as poorly defined hybrids of these two architectures. The formation of icosahedral capsids with different triangulation numbers has been previously reported for other viruses (Venkatakrishnan and Zlotnick, 2016;Jung et al, 2019), which is not wholly unexpected considering the close symmetry relationships between related icosahedral triangulations (Prasad and Schmid, 2012).…”

Section: A B D Csupporting

confidence: 69%

Bacteriophage MS2 displays unreported capsid variability assembling T = 4 and mixed capsids

Garrido

Crone

Ramlaul

et al. 2019

Molecular Microbiology

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Bacteriophage MS2 is a positive-sense, singlestranded RNA virus encapsulated in an asymmetric T = 3 pseudo-icosahedral capsid. It infects Escherichia coli through the F-pilus, in which it binds through a maturation protein incorporated into its capsid. Cryogenic electron microscopy has previously shown that its genome is highly ordered within virions, and that it regulates the assembly process of the capsid. In this study, we have assembled recombinant MS2 capsids with non-genomic RNA containing the capsid incorporation sequence, and investigated the structures formed, revealing that T = 3, T = 4 and mixed capsids between these two triangulation numbers are generated, and resolving structures of T = 3 and T = 4 capsids to 4 Å and 6 Å respectively. We conclude that the basic MS2 capsid can form a mix of T = 3 and T = 4 structures, supporting a role for the ordered genome in favouring the formation of functional T = 3 virions.Abbreviations: CP, coat protein; IAU, icosahedral asymmetric unit; MP, maturation protein; VLP, virus-like particle.

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Section: A B D Csupporting

confidence: 69%

Bacteriophage MS2 displays unreported capsid variability assembling T = 4 and mixed capsids

Garrido

Crone

Ramlaul

et al. 2019

Molecular Microbiology

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“…The recombinant version of the HBV e antigen used to solve the structure was Cp(‐10)149, and the C‐terminal sequence was based on earlier work . This was also consistent with the HBcAg construct Cp149 used for many structural studies . More recent work shows that HBeAg C‐terminal processing occurs in the Golgi apparatus by the transmembrane protein convertase furin.…”

Section: Discussionsupporting

confidence: 81%

Capsids of hepatitis B virus e antigen with authentic C termini are stabilized by electrostatic interactions

et al. 2019

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The hepatitis B virus e antigen, an alternative transcript of the core gene, is a secreted protein that maintains viral persistence. The physiological form has extended C termini relative to Cp(‐10)149, the construct used in many studies. To examine the role of the C termini, we expressed the constructs Cp(‐10)151 and Cp(‐10)154, which have additional arginine residues. Both constructs when treated with reductant formed capsids more efficiently than Cp(‐10)149. These capsids were also substantially more stable, as measured by thermal denaturation and resistance to urea dissociation. Mutagenesis suggests that electrostatic interactions between the additional arginine residues and glutamate residues on adjacent subunits play a role in the extra stabilization. These findings have implications for the physiological role and biotechnological potential of this protein.

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“…The assembly of HBcAc VLPs also induces changes in mean hydrophobicity around aromatic amino acids as capsid assembly relies on hydrophobic interaction forces (Venkatakrishnan & Zlotnick, 2016;Wynne et al, 1999). Tyrosine-132 is especially important for the assembly (Bourne, Katen, Fulz, Packianathan, & Zlotnick, 2009).…”

mentioning

confidence: 99%

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

Rüdt

Vormittag

Hillebrandt

et al. 2019

Biotech & Bioengineering

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Virus‐like particles (VLPs) have shown great potential as biopharmaceuticals in the market and in clinics. Nonenveloped, in vivo assembled VLPs are typically disassembled and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At the industrial scale, cross‐flow filtration (CFF) is the method of choice for performing reassembly by diafiltration. Here, we developed an experimental CFF setup with an on‐line measurement loop for the implementation of process analytical technology (PAT). The measurement loop included an ultraviolet and visible (UV/Vis) spectrometer as well as a light scattering photometer. These sensors allowed for monitoring protein concentration, protein tertiary structure, and protein quaternary structure. The experimental setup was tested with three Hepatitis B core Antigen (HBcAg) variants. With each variant, three reassembly processes were performed at different transmembrane pressures (TMPs). While light scattering provided information on the assembly progress, UV/Vis allowed for monitoring the protein concentration and the rate of VLP assembly based on the microenvironment of Tyrosine‐132. VLP formation was verified by off‐line dynamic light scattering (DLS) and transmission electron microscopy (TEM). Furthermore, the experimental results provided evidence of aggregate‐related assembly inhibition and showed that off‐line size‐exclusion chromatography does not provide a complete picture of the particle content. Finally, a Partial‐Least Squares (PLS) model was calibrated to predict VLP concentrations in the process solution. Q 2 values of 0.947–0.984 were reached for the three HBcAg variants. In summary, the proposed experimental setup provides a powerful platform for developing and monitoring VLP reassembly steps by CFF.

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The Structural Biology of Hepatitis B Virus: Form and Function

Cited by 132 publications

References 178 publications

Bacteriophage MS2 displays unreported capsid variability assembling T = 4 and mixed capsids

Bacteriophage MS2 displays unreported capsid variability assembling T = 4 and mixed capsids

Capsids of hepatitis B virus e antigen with authentic C termini are stabilized by electrostatic interactions

Process monitoring of virus‐like particle reassembly by diafiltration with UV/Vis spectroscopy and light scattering

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