scholarly journals Author response: Hepatitis B virus core protein allosteric modulators can distort and disrupt intact capsids

2017 ◽  
Author(s):  
Christopher John Schlicksup ◽  
Joseph Che-Yen Wang ◽  
Samson Francis ◽  
Balasubramanian Venkatakrishnan ◽  
William W Turner ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Author Response ◽  
Allosteric Modulators ◽  
Virus Core ◽  
B Virus

scholarly journals Hepatitis B virus core protein allosteric modulators can distort and disrupt intact capsids

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Christopher John Schlicksup ◽  
Joseph Che-Yen Wang ◽  
Samson Francis ◽  
Balasubramanian Venkatakrishnan ◽  
William W Turner ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Binding Sites ◽  
Core Protein ◽  
Spectroscopic Studies ◽  
Allosteric Modulators ◽  
Virus Core ◽  
B Virus ◽  
High Resolution Reconstruction ◽  
Direct Acting

Defining mechanisms of direct-acting antivirals facilitates drug development and our understanding of virus function. Heteroaryldihydropyrimidines (HAPs) inappropriately activate assembly of hepatitis B virus (HBV) core protein (Cp), suppressing formation of virions. We examined a fluorophore-labeled HAP, HAP-TAMRA. HAP-TAMRA induced Cp assembly and also bound pre-assembled capsids. Kinetic and spectroscopic studies imply that HAP-binding sites are usually not available but are bound cooperatively. Using cryo-EM, we observed that HAP-TAMRA asymmetrically deformed capsids, creating a heterogeneous array of sharp angles, flat regions, and outright breaks. To achieve high resolution reconstruction (<4 Å), we introduced a disulfide crosslink that rescued particle symmetry. We deduced that HAP-TAMRA caused quasi-sixfold vertices to become flatter and fivefold more angular. This transition led to asymmetric faceting. That a disordered crosslink could rescue symmetry implies that capsids have tensegrity properties. Capsid distortion and disruption is a new mechanism by which molecules like the HAPs can block HBV infection.

scholarly journals Dominant negative mutants of the duck hepatitis B virus core protein interfere with RNA pregenome packaging and viral DNA synthesis

Hepatology ◽  
1999 ◽  
Vol 30 (1) ◽  
pp. 308-315 ◽  
Author(s):  
Fritz von Weizsäcker ◽  
Josef Köck ◽  
Stefan Wieland ◽  
Wolf-Bernhard Offensperger ◽  
Hubert E. Blum
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Dna Synthesis ◽  
Core Protein ◽  
Dominant Negative ◽  
Viral Dna ◽  
Duck Hepatitis B Virus ◽  
Virus Core ◽  
Duck Hepatitis ◽  
B Virus

scholarly journals APOBEC3G directly binds Hepatitis B virus core protein in cell and cell free systems

2010 ◽  
Vol 151 (2) ◽  
pp. 213-219 ◽  
Author(s):  
Dongjiu Zhao ◽  
Xianfeng Wang ◽  
Guohua Lou ◽  
Guoping Peng ◽  
Jie Li ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Virus Core ◽  
B Virus

scholarly journals Transbody against virus core protein potently inhibits hepadnavirus replication in vivo : evidence from a duck model of hepatitis B virus

2017 ◽  
Vol 174 (14) ◽  
pp. 2261-2272 ◽  
Author(s):  
Yiping Li ◽  
Zhengwen Liu ◽  
Lingyun Hui ◽  
Xi Liu ◽  
Ai Feng ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Virus Core ◽  
B Virus

scholarly journals Hepatitis B Virus Capsids Have Diverse Structural Responses to Small-Molecule Ligands Bound to the Heteroaryldihydropyrimidine Pocket

2016 ◽  
Vol 90 (8) ◽  
pp. 3994-4004 ◽  
Author(s):  
Balasubramanian Venkatakrishnan ◽  
Sarah P. Katen ◽  
Samson Francis ◽  
Srinivas Chirapu ◽  
M. G. Finn ◽  
...  
Keyword(s):  
Life Cycle ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Drug Design ◽  
Quaternary Structure ◽  
Core Protein ◽  
Viral Life Cycle ◽  
Structural Basis ◽  
Allosteric Modulators ◽  
B Virus

ABSTRACTThough the hepatitis B virus (HBV) core protein is an important participant in many aspects of the viral life cycle, its best-characterized activity is self-assembly into 240-monomer capsids. Small molecules that target core protein (core protein allosteric modulators [CpAMs]) represent a promising antiviral strategy. To better understand the structural basis of the CpAM mechanism, we determined the crystal structure of the HBV capsid in complex with HAP18. HAP18 accelerates assembly, increases protein-protein association more than 100-fold, and induces assembly of nonicosahedral macrostructures. In a preformed capsid, HAP18 is found at quasiequivalent subunit-subunit interfaces. In a detailed comparison to the two other extant CpAM structures, we find that the HAP18-capsid structure presents a paradox. Whereas the two other structures expanded the capsid diameter by up to 10 Å, HAP18 caused only minor changes in quaternary structure and actually decreased the capsid diameter by ∼3 Å. These results indicate that CpAMs do not have a single allosteric effect on capsid structure. We suggest that HBV capsids present an ensemble of states that can be trapped by CpAMs, indicating a more complex basis for antiviral drug design.IMPORTANCEHepatitis B virus core protein has multiple roles in the viral life cycle—assembly, compartment for reverse transcription, intracellular trafficking, and nuclear functions—making it an attractive antiviral target. Core protein allosteric modulators (CpAMs) are an experimental class of antivirals that bind core protein. The most recognized CpAM activity is that they accelerate core protein assembly and strengthen interactions between subunits. In this study, we observe that the CpAM-binding pocket has multiple conformations. We compare structures of capsids cocrystallized with different CpAMs and find that they also affect quaternary structure in different ways. These results suggest that the capsid “breathes” and is trapped in different states by the drug and crystallization. Understanding that the capsid is a moving target will aid drug design and improve our understanding of HBV interaction with its environment.

Phosphorylation of hepatitis B virus core C-terminally truncated protein (Cp149) by PKC increases capsid assembly and stability

2008 ◽  
Vol 416 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Hang Kang ◽  
Jaehoon Yu ◽  
Guhung Jung
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Virus Titre ◽  
Capsid Assembly ◽  
Human Hepatoma Cells ◽  
Virus Core ◽  
C Terminus ◽  
B Virus

The HBV (hepatitis B virus) core is a phosphoprotein whose assembly, replication, encapsidation and localization are regulated by phosphorylation. It is known that PKC (protein kinase C) regulates pgRNA (pregenomic RNA) encapsidation by phosphorylation of the C-terminus of core, which is a component packaged into capsid. Neither the N-terminal residue phosphorylated by PKC nor the role of the C-terminal phosphorylation have been cleary defined. In the present study we found that HBV Cp149 (core protein C-terminally truncated at amino acid 149) expressed in Escherichia coli was phosphorylated by PKC at Ser106. PKC-mediated phosphorylation increased core affinity, as well as assembly and capsid stability. In vitro phosphorylation with core mutants (S26A, T70A, S106A and T114A) revealed that the Ser106 mutation inhibited phosphorylation of core by PKC. CD analysis also revealed that PKC-mediated phosphorylation stabilized the secondary structure of capsid. When either pCMV/FLAG-Cp149[WT (wild-type)] or pCMV/FLAG-S106A Cp149 was transfected into Huh7 human hepatoma cells, mutant capsid level was decreased by 2.06-fold with the S106A mutant when compared with WT, although the same level of total protein was expressed in both cases. In addition, when pUC1.2x and pUC1.2x/S106A were transfected, mutant virus titre was decreased 2.31-fold compared with WT virus titre. In conclusion, PKC-mediated phosphorylation increased capsid assembly, stability and structural stability.

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