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Kim J, Wu J. A theoretical study of SRPK interaction with the flexible domains of hepatitis B capsids. Biophys J 2015; 107:1453-61. [PMID: 25229152 DOI: 10.1016/j.bpj.2014.07.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/27/2014] [Accepted: 07/15/2014] [Indexed: 12/22/2022] Open
Abstract
Hepatitis B virus (HBV) controls genome encapsidation and reverse transcription from a single-stranded RNA to a double-stranded DNA through the flexible C-terminal domain (CTD) of the capsid proteins. Although the microscopic structure of the nucleocapsid plays a critical role in the life cycle of HBV, the location of CTD residues at different stages of viral replication remains poorly understood. In this work, we report the radial distributions of individual amino-acid residues of the CTD tails for both empty and RNA-containing HBV capsids by using a coarse-grained model for the key biological components and the classical density functional theory. The density functional theory calculations reveal substantial exposure of the CTD residues outside the capsid, in particular when it is devoid of any nucleic materials. The outermost layer of the capsid surface mainly consists of residues from (170)Ser-(175)Arg of the CTD tails, i.e., the serine-arginine protein kinase binding motif. The theoretical description corroborates recent in vitro studies that show a transient CTD distribution captured by serine-arginine protein kinase binding. We have also investigated the nucleocapsid structural changes due to phosphorylation of serine residues and shown a correlation between the CTD location and the internal distribution of RNA segments.
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Affiliation(s)
- Jehoon Kim
- Department of Chemical and Environmental Engineering, University of California, Riverside, California
| | - Jianzhong Wu
- Department of Chemical and Environmental Engineering, University of California, Riverside, California.
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Porterfield JZ, Dhason MS, Loeb DD, Nassal M, Stray SJ, Zlotnick A. Full-length hepatitis B virus core protein packages viral and heterologous RNA with similarly high levels of cooperativity. J Virol 2010; 84:7174-84. [PMID: 20427522 PMCID: PMC2898219 DOI: 10.1128/jvi.00586-10] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 04/22/2010] [Indexed: 01/01/2023] Open
Abstract
A critical feature of a viral life cycle is the ability to selectively package the viral genome. In vivo, phosphorylated hepatitis B virus (HBV) core protein specifically encapsidates a complex of pregenomic RNA (pgRNA) and viral polymerase; it has been suggested that packaging is specific for the complex. Here, we test the hypothesis that core protein has intrinsic specificity for pgRNA, independent of the polymerase. For these studies, we also evaluated the effect of core protein phosphorylation on assembly and RNA binding, using phosphorylated core protein and a phosphorylation mimic in which S155, S162, and S170 were mutated to glutamic acid. We have developed an in vitro system where capsids are disassembled and assembly-active core protein dimer is purified. With this protein, we have reassembled empty capsids and RNA-filled capsids. We found that core protein dimer bound and encapsidated both the HBV pregenomic RNA and heterologous RNA with high levels of cooperativity, irrespective of phosphorylation. In direct competition assays, no specificity for pregenomic RNA was observed. This suggests that another factor, such as the viral polymerase, is required for specific packaging. These results also beg the question of what prevents HBV core protein from assembling on nonviral RNA, preserving the protein for virus production.
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Affiliation(s)
- J. Zachary Porterfield
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
| | - Mary Savari Dhason
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
| | - Daniel D. Loeb
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
| | - Michael Nassal
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
| | - Stephen J. Stray
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
| | - Adam Zlotnick
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, McArdle Laboratory for Cancer Research, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, University Hospital Freiburg, Internal Medicine 2, Molecular Biology, Hugstetter Strasse 55, D-79106 Freiburg, Germany, Department of Microbiology, University of Mississippi, Jackson, Mississippi 39216
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Hui EKW, Chen KL, Lo SJ. Hepatitis B virus maturation is affected by the incorporation of core proteins having a C-terminal substitution of arginine or lysine stretches. J Gen Virol 1999; 80 ( Pt 10):2661-2671. [PMID: 10573159 DOI: 10.1099/0022-1317-80-10-2661] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Assembly of replication-competent hepadnavirus nucleocapsids requires interaction of core protein, polymerase and encapsidation signal (epsilon) with viral pregenomic RNA. The N-terminal portion (aa 1-149) of the core protein is able to self-assemble into nucleocapsids, whereas the C-terminal portion (aa 150-183) is known to interact with pregenomic RNA. In this study, two hepatitis B virus (HBV) core mutants (C144Arg and C144Lys) in which the C-terminal SPRRR (Ser-Pro-Arg-Arg-Arg) motif was replaced by a stretch of arginine or lysine residues were generated to test their role in pregenome encapsidation and virus maturation. Mutant or wild-type core-expression plasmids were co-transfected with a core-negative plasmid into human hepatoma HuH-7 cells to compare trans-complementation efficiency for virus replication. Both low- and high-density capsids were present in -the cytoplasm and culture medium of HuH-7 cells in all transfections. Nucleocapsids formed by C144Arg and C144Lys, however, lost the endogenous polymerase activity to repair HBV DNA. Furthermore, in co-transfection of pHBVC144Arg or pHBVC144Lys with a plasmid which produces replication-competent nucleocapsids, the HBV DNA repairing signal was reduced 40- to 80-fold. This is probably due to formation of mosaic particles of wild-type and mutant cores. Results indicated that the SPRRR motif at the core protein C terminus is important for HBV DNA replication and maturation. Additionally, triple-plasmid transfection experiments showed that nucleocapsids containing various amounts of C144Arg and wild-type core proteins exhibited a bias in selecting a shorter pregenome for encapsidation and DNA replication. It is therefore suggested that unknown factors are also involved in HBV pregenome packaging.
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Affiliation(s)
- Eric Ka-Wai Hui
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
| | - Kun-Lin Chen
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
| | - Szecheng J Lo
- Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China 1
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