The self-assembly of the cowpea strain of southern bean mosaic virus: Formation of T = 1 and T = 3 nucleoprotein particles

Savithri, H.S.; Erickson, John W.

doi:10.1016/0042-6822(83)90482-8

Cited by 61 publications

(33 citation statements)

References 13 publications

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“…Structural study of the Grimsby virus, a strain genetically closely related with VA387, revealed a spherical structure of the P dimer moiety in a capsomer (4), suggesting that the isolated P dimer is a spherical structure that fits easily in an icosahedral particle (15). The single peak of the P particle in gel filtrations indicates that the P proteins must be arranged into a low-energy order, consis- (1,6,8,24,30). Thus, the formation of subviral particles by truncated viral capsid proteins is a common phenomenon.…”

Section: Discussionmentioning

confidence: 99%

“…This molecular switch is more common in plant viruses. When the N-terminal arms of the capsid protein were removed, the mutant capsids of many plant viruses assembled into Tϭ1 particles (6,8,24,30). However, additional mechanisms may also exist: the NV mutant lacking the N-terminal arm is able to assemble into a Tϭ3 capsid (2), while both Tϭ1 and Tϭ3 particles could be observed when the NV full-length capsid protein was expressed in insect cells (36).…”

Section: Vol 79 2005mentioning

confidence: 99%

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The P Domain of Norovirus Capsid Protein Forms a Subviral Particle That Binds to Histo-Blood Group Antigen Receptors

Tan

Jiang

2005

J Virol

202

304

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Norovirus is the most important cause of nonbacterial acute gastroenteritis. We have shown previously that the isolated P domain containing the hinge forms a dimer and binds to histo-blood group antigen (HBGA) receptors with a low affinity (M. Tan, R. S. Hegde, and X. Jiang, J. Virol. 78:6233-6242, 2004). Here, we reported that the P domain of VA387 without the hinge forms a small particle with a significantly increased receptor binding affinity. An end-linked oligopeptide containing one or more cysteines promoted P-particle formation by forming intermolecular disulfide bridges. The binding sensitivity of the P particle to HBGAs was enhanced >700-fold compared to the P dimer, which was comparable to that of virus-like particles. The binding specificity of the P particle was further confirmed by strong binding to the Caco-2 cells, a human colon carcinoma cell line. This binding enhancement was observed in the P particles of both norovirus GI and GII strains. The P particle is estimated to contain 12 P dimers, in which the P2 subdomain builds up the outer layer, while the P1 subdomain forms the internal core. Taken together, our data indicate that the P domain is involved not only in dimerization but also in polymerization of the protein during the capsid assembling. The enhanced receptor binding of the P particle reflects the intrinsic feature of the viral capsid. The easy production of the P particle and its strong binding to HBGAs suggest that the P particle is useful in studying pathogenesis and morphogenesis of norovirus and candidates for antiviral or vaccine development.Norovirus, previously called Norwalk-like virus or small round structured virus, is the most important viral pathogen of epidemic acute gastroenteritis in both developed and developing countries (9, 10). Recent advances in understanding of norovirus-host interaction and the viral receptors have opened a new approach to study the host range and pathogenesis (18, 31). Noroviruses recognize human histo-blood group antigens (HBGAs) as receptors, which are complex carbohydrates present on red blood cells and mucosal epithelium or as free antigens in biological fluids, such as saliva, milk, and intestinal contents (25,29). The recognition of HBGAs by noroviruses is strain specific, and eight distinct receptor-binding patterns have been identified (13,14,16,17,19,26). The linkage of norovirus binding to HBGAs with clinical infection has been demonstrated in human volunteer studies. In the case of the prototype Norwalk virus (NV), for example, individuals of nonsecretors were naturally resistant to NV infection following the challenge (23). It seems logical to predict that each virus strain of the other binding patterns has its own host range defined by host blood type, although a recent human volunteer study of another norovirus, the Snow Mountain virus, did not reveal clear association between infection and host blood type (22).Norovirus belongs to the family Caliciviridae. It contains a positive-strand, polyadenylated RNA genome of ϳ7.7 kb that i...

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Section: Discussionmentioning

confidence: 99%

Section: Vol 79 2005mentioning

confidence: 99%

The P Domain of Norovirus Capsid Protein Forms a Subviral Particle That Binds to Histo-Blood Group Antigen Receptors

Tan

Jiang

2005

J Virol

202

304

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“…A dramatic example of a scaffolding-like function for nucleic acids has been observed in Southern cowpea mosiac virus. Deleting the highly basic, RNA-interacting N terminus of the coat protein results in the production of Tϭ1, as opposed to Tϭ3, capsids (44). Similarly, the nature of the RNA packaged in Brome mosaic virus can determine whether Tϭ3 or 120-subunit capsids are formed (35).…”

Section: Discussionmentioning

confidence: 99%

φX174 Genome-Capsid Interactions Influence the Biophysical Properties of the Virion: Evidence for a Scaffolding-Like Function for the Genome during the Final Stages of Morphogenesis

Hafenstein

Fane

2002

J Virol

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During the final stages of X174 morphogenesis, there is an 8.5-Å radial collapse of coat proteins around the packaged genome, which is tethered to the capsid's inner surface by the DNA-binding protein. Two approaches were taken to determine whether protein-DNA interactions affect the properties of the mature virion and thus the final stages of morphogenesis. In the first approach, genome-capsid associations were altered with mutant DNA-binding proteins. The resulting particles differed from the wild-type virion in density, native gel migration, and host cell recognition. Differences in native gel migration were especially pronounced. However, no differences in protein stoichiometries were detected. An extragenic second-site suppressor of the mutant DNA-binding protein restores all assayed properties to near wild-type values. In the second approach, X174 was packaged with foreign, single-stranded, covalently closed, circular DNA molecules identical in length to the X174 genome. The resulting particles exhibited native gel migration rates that significantly differed from the wild type. The results of these experiments suggest that the structure of the genome and/or its association with the capsid's inner surface may perform a scaffolding-like function during the procapsid-tovirion transition.Unlike many double-stranded DNA (dsDNA) viruses which use one scaffolding protein (14, 34), X174 morphogenesis is dependent on two species (30). Together, these two proteins perform the full spectrum of functions found in one-protein systems. However, after procapsid assembly, the final stages of X174 morphogenesis differ. In dsDNA systems, procapsids expand during packaging (32,37,41), and the genome forms a dense core (18). In contrast, X174 morphogenesis concludes with the collapse of coat proteins around the single-stranded genome, which is associated with the inner surface of the capsid (15,16,31,38,39).As illustrated in Fig. 1, X174 genome replication is coupled to DNA packaging. The preinitiation complex, consisting of the host cell rep and viral A and C proteins, associates with the procapsid forming the 50S complex (21,40). The viral A protein binds the origin of replication in replicative-form DNA. This is both necessary and sufficient for packaging specificity (3,4,26). Upon binding, protein A nicks the origin (47) and forms a covalent ester bond with the DNA (19). After one round of rolling circle synthesis, protein A cuts and ligates the newly generated origin, generating a circular single-stranded molecule (7,20). This packaging mechanism produces precise genomes of identical length (4).The highly basic DNA-binding protein (J) enters the procapsid, along with the single-stranded DNA (ssDNA) genome, (27), associating with the genome via charge-charge interactions (13, 33). Once in the procapsid, the C terminus binds to a coat protein cleft (38,39). This may facilitate further interactions with a small cluster of adjacent basic capsid amino acids. Accordingly, a portion of the packaged DNA (8 to 10%) is icosahedral...

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“…3,4 Table 1 describes the capsid protein properties and the cleavages created by proteolysis that lead to reassembly into TZ1 particles. To produce the TZ1 particles of SBMV and AlMV, the capsid protein was exposed to trypsin; 4,6,7,9 for SeMV, recombinant proteins of two different lengths were reassembled; 10,11 and for BMV, TZ1 particles formed after cleavage of the native coat protein by, presumably, endogenous proteases. 14 We previously reported the in vitro reassembly of the coat protein of BMV into TZ1 particles after loss of 35 amino acid residues from the N terminus, as well as its crystallization for X-ray diffraction analysis.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic Structure of the T=1 Particle of Brome Mosaic Virus

Larson

Lucas

McPherson

2005

Journal of Molecular Biology

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TZ1 icosahedral particles of amino terminally truncated brome mosaic virus (BMV) protein were created by treatment of the wild-type TZ3 virus with 1 M CaCl 2 and crystallized from sodium malonate. Diffraction data were collected from frozen crystals to beyond 2.9 Å resolution and the structure determined by molecular replacement and phase extension. The particles are composed of pentameric capsomeres from the wild-type virions which have reoriented with respect to the original particle pentameric axes by rotations of 378, and formed tenuous interactions with one another, principally through conformationally altered C-terminal polypeptides. Otherwise, the pentamers are virtually superimposable upon those of the original TZ3 BMV particles. The TZ1 particles, in the crystals, are not perfect icosahedra, but deviate slightly from exact symmetry, possibly due to packing interactions. This suggests that the TZ1 particles are deformable, which is consistent with the loose arrangement of pentamers and latticework of holes that penetrate the surface. Atomic force microscopy showed that the TZ3 to TZ1 transition could occur by shedding of hexameric capsomeres and restructuring of remaining pentamers accompanied by direct condensation. Knowledge of the structures of the BMV wild-type and TZ1 particles now permit us to propose a tentative model for that process. A comparison of the BMV TZ1 particles was made with the reassembled TZ1 particles produced from the coat protein of trypsin treated alfalfa mosaic virus (AlMV), another bromovirus. There is little resemblance between the two particles. The BMV particle, with a maximum diameter of 195 Å , is made from distinctive pentameric capsomeres with large holes along the 3-fold axis, while the AlMV particle, of approximate maximum diameter 220 Å , has subunits closely packed around the 3-fold axis, large holes along the 5-fold axis, and few contacts within pentamers. In both particles crucial linkages are made about icosahedral dyads.

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The self-assembly of the cowpea strain of southern bean mosaic virus: Formation of T = 1 and T = 3 nucleoprotein particles

Cited by 61 publications

References 13 publications

The P Domain of Norovirus Capsid Protein Forms a Subviral Particle That Binds to Histo-Blood Group Antigen Receptors

The P Domain of Norovirus Capsid Protein Forms a Subviral Particle That Binds to Histo-Blood Group Antigen Receptors

φX174 Genome-Capsid Interactions Influence the Biophysical Properties of the Virion: Evidence for a Scaffolding-Like Function for the Genome during the Final Stages of Morphogenesis

Crystallographic Structure of the T=1 Particle of Brome Mosaic Virus

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