Protein disk of tobacco mosaic virus at 2.8 Å resolution showing the interactions within and between subunits

Bloomer, A.C.; Champness, J.N.; Bricogne, G.; Staden, Rodger; Klug, A.

doi:10.1038/276362a0

Cited by 430 publications

(252 citation statements)

References 29 publications

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“…What the comparison between PVX and PMV proteins suggests is that there will be differences between the amino and carboxyl termini, but that there will be a similar distribution of a-helical segments in the middles of the protein chains. This is what might be expected if the amino and carboxyl termini lie at a large radius, towards the outside of the virus particle, as they do in TMV particles (Stubbs et al, 1977;Bloomer et al, 1978).…”

Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 73%

“…Although combined predictions have been shown to be no more reliable than any individual method (Nishikawa, 1983), regions strongly predicted by several methods to have particular conformations do seem to be more likely to be correct (Nishikawa & Ooi, 1986). We believed that the combined predictions would give meaningful results for PVX and PMV because a test on TMV protein correctly predicted the four major helical segments as revealed in the X-ray diffraction studies on TMV (Stubbs et al, 1977) and TMV protein (Bloomer et al, 1978). Three of the four a-helical segments were clearly predicted by at least five methods and the fourth by at least four.…”

Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 99%

“…This suggests that the tertiary structure could be such that the el-helices align themselves in pairs. This occurs in TMV protein, where the folding of the amino and carboxyl halves of the polypeptide chain are quite similar and where there is also an approximate twofold symmetry between them (Bloomer et al, 1978;McLachlan et al, 1980).…”

Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 99%

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A Comparison between the Predicted Secondary Structures of Potato Virus X and Papaya Mosaic Virus Coat Proteins

Sawyer

Tollin

Wilson

1987

Journal of General Virology

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Comparison of the predicted secondary structures of the coat proteins of the potexviruses potato X and papaya mosaic, on the basis of a combination of prediction methods, shows that although the proteins differ at their amino termini, and possibly at their carboxyl termini, they are similar in the distribution of e-helical segments in the central regions of the protein chains. There is an approximate twofold symmetry in the distribution of predicted e-helical segments between the amino and carboxyl halves of the molecules.The potexviruses potato virus X (PVX) and papaya mosaic virus (PMV) have elongated, flexuous rod-shaped particles with modal lengths of 515 nm and 530 nm, respectively, and diameters of about 13 nm (Francki et al., 1985). The capsid protein of both viruses consists of a helical arrangement of subunits, with a pitch of about 3.4 nm, protecting a single strand of RNA at a radius of about 3.3 nm (Francki et al., 1985). Particles of PVX have 8.875 protein subunits per helix turn (ToUin et al., 1980) and those of PMV have 8-750 (Tollin et al., 1979). The quaternary structures of the two viruses are thus very similar, and are also similar to those of other potexviruses (Richardson et al., 1981).The primary structure of PVX (Morozov et al., 1983) and PMV (Short et al., 1986) coat proteins have been determined. Short et al. (1986) have compared the two sequences and drawn attention to a number of homologous regions in the two proteins. The PVX polypeptide chain is 25 residues longer than that of PMV but the optimal alignment of the two sequences puts 23 of these extra residues in an extension to the amino terminus of the PVX protein. The proteins have 38~ identity when aligned by the program BESTFIT (Devereux et al., 1984), which rises to 61 when chemically similar, rather than identical, residues are matched. The identity is most marked between residues 120 and 160 in PMV, with 28 of the 40 residues matching exactly and a further five residues changed conservatively. It is of interest, therefore, to see whether there are similarities in the predicted secondary structures of the two proteins. Whereas the ultimate test of the accuracy of such predictions must await more detailed X-ray diffraction analysis, the predictions themselves may help in this analysis.Comparing the two sequences with those available in current data bases using the Wisconsin package (Devereux et al., 1984) produced no significant homologies to other proteins and attempts to align the sequence of tobacco mosaic virus (TMV) coat protein with that of either PMV or PVX did not produce a satisfactory alignment, even when gaps were allowed. The more thorough search algorithm of Lyall et al. (1986) also failed to produce any significant matches with other proteins.The procedure we have used to perform the predictions is as follows. The combination of methods suggested by Eliopoulos et al. (1982) has been extended by him to include the procedures of McLachlan (1978) and Kabat & Wu (1973) and it is this combined prediction which we prese...

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Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 73%

Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 99%

Section: Ill I{i I I I I~l I I I I I I I "I I I I I I']i I-i I] Iliiimentioning

confidence: 99%

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A Comparison between the Predicted Secondary Structures of Potato Virus X and Papaya Mosaic Virus Coat Proteins

Sawyer

Tollin

Wilson

1987

Journal of General Virology

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“…The eight-stranded antiparallel virus fold has now been found in many RNA and DNA viral capsids 39 , yet its presence is not entirely universal (for example in the plant RNA tobacco mosaic virus 54,55 , in the RNA phage MS2 56 and in the animal RNA Sindbis virus 57 ). Hence, the eight-stranded antiparallel β-barrel fold is not a prerequisite for assembly of icosahedral structures 58 .…”

Section: Evolutionmentioning

confidence: 99%

Atomic structure of single-stranded DNA bacteriophage ΦX174 and its functional implications

McKenna

Xia

Willingmann

et al. 1992

Nature

216

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The mechanism of DNA ejection, viral assembly and evolution are related to the structure of bacteriophage ΦX174. The F protein forms a T = 1 capsid whose major folding motif is the eightstranded antiparallel β barrel found in many other icosahedral viruses. Groups of 5 G proteins form 12 dominating spikes that enclose a hydrophilic channel containing some diffuse electron density. Each G protein is a tight β barrel with its strands running radially outwards and with a topology similar to that of the F protein. The 12 'pilot' H proteins per virion may be partially located in the putative ion channel. The small, basic J protein is associated with the DNA and is situated in an interior cleft of the F protein. Tentatively, there are three regions of partially ordered DNA structure, accounting for about 12% of the total genome.Bacteriophage ΦX174 is a small icosahedral virus that contains a single-stranded, closed circular DNA molecule with 5,386 nucleotide bases (for a recent review, see ref. 1). Of the 11 gene products, four (J, F, G and H) participate in the structure of the virion. There are 60 copies each of the J, F and G proteins and 12 copies of the H protein per virion [2][3][4] (Table 1). Electron microscopy of shadowed or negatively stained particles [5][6][7][8] , as well as a threedimensional reconstruction of frozen-hydrated virions (Fig. 1a), clearly show large spikes at the vertices of the icosahedral particles (N.H.O., T.S.B., P.W. and N.L.I., manuscript in preparation). These spikes are about 32 Å long and have a mean diameter of 70 Å. Edgell et al. 3 have shown that these spikes, which can be removed from the capsid with 4 M urea treatment, are composed of G and H proteins. Assuming all 12 spikes are identical, then each spike will contain five G and one H protein 2 . The capsid itself has an external diameter of roughly 260 Å, with a protein shell that is about 30 Å thick, and contains the F and J proteins as well as the single-stranded (ss) DNA. The phage recognizes a lipopolysaccharide (LPS) receptor on the outer cell membrane of Escherichia coli [8][9][10][11] . Host range mutants, which determine which strains of E. coli are infected by ΦX174, map into the F, G and H genes [12][13][14][15] The infectious virion has a relative molecular mass of 6.2 × 10 6 (M r 6,200K) (26% is DNA) 32 . Lysates of infected E. coli contain two components which can be separated by sedimentation through a sucrose gradient 32,33 . The fast band contains the infectious 114S particles whereas the slow band contains noninfectious, 70S particles 32,34,35 . The latter contains about 20% of the normal DNA content with all of the genome represented in the population of particles. Both types of particles can be crystallized into isomorphous monoclinic crystals with space group P2 1 , and cell dimensions a = 305.6, b = 360.8, c = 299.5 Å, β = 92.89° that diffract at least to 2.6-Å resolution 33 . The asymmetric unit of the crystal cell contains one complete particle. We report here the three-dimensional structure...

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“…The particles of two other rod-shaped plant virus groups, the potexviruses (Koenig et al, 1978;Sawyer et al, 1987) and tobamoviruses (Bloomer et al, 1978) are also known to have the N and C termini of their coat protein chains exposed on the external surfaces. The observed coat protein degradation during storage of tobraviruses (Mayo & Cooper, 1973;Mayo et al, 1974), which also have a rod-shaped morphology, may indicate the surface location of N and C termini of their coat proteins.…”

mentioning

confidence: 99%

The N and C Termini of the Coat Proteins of Potyviruses Are Surface-located and the N Terminus Contains the Major Virus-specific Epitopes

Shukla

Strike

Tracy

et al. 1988

Journal of General Virology

281

241

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SUMMARYMild proteolysis by trypsin of particles of six potyviruses (bean yellow mosaic virus, clover yellow vein virus, Johnson grass mosaic virus, passion-fruit woodiness virus, potato virus Y and watermelon mosaic virus II) revealed that the N-and C-terminal regions of their coat protein are exposed on the particles' surfaces. The enzyme treatment removed the N-terminal region (30 to 67 amino acids long, depending on the virus) and 18 to 20 amino acids from the C terminus of the coat proteins, leaving a fully assembled virus particle composed of coat protein cores consisting of 216 or 218 amino acid residues. These core particles were indistinguishable from untreated native particles in an electron microscope and were still infectious. The core particles lacked the virus-specific surface epitopes that are recognized by the bulk of the polyclonal antibodies raised against the whole virus particles. Epitopes thought to be groupspecific were located in the trypsin-resistant core protein region. The implications of these findings are discussed in relation to the similar surface location of the N-and Cterminal regions of the coat protein of other rod-shaped plant viruses and the observed common structural features displayed by isometric plant and animal viruses.

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Protein disk of tobacco mosaic virus at 2.8 Å resolution showing the interactions within and between subunits

Cited by 430 publications

References 29 publications

A Comparison between the Predicted Secondary Structures of Potato Virus X and Papaya Mosaic Virus Coat Proteins

A Comparison between the Predicted Secondary Structures of Potato Virus X and Papaya Mosaic Virus Coat Proteins

Atomic structure of single-stranded DNA bacteriophage ΦX174 and its functional implications

The N and C Termini of the Coat Proteins of Potyviruses Are Surface-located and the N Terminus Contains the Major Virus-specific Epitopes

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