Small RNA Viruses Co-infecting the Pine Emperor Moth (Nudaurelia cytherea capensis)

The structure of Nudaurelia capensis 3 virus (N3V), a single-stranded RNA virus, was determined to 2.8 A Ê resolution. Triclinic crystals (a = 413.6, b = 410.2, c = 419.7 A Ê , = 59.13, = 58.9, = 64.0 ) diffracted X-rays beyond 2.7 A Ê resolution. The unit cell contained one icosahedral virus particle, providing 60-fold noncrystallographic symmetry (n.c.s.) and structural redundancy. The particle orientation in the unit cell was determined by self-rotation function analyses. Initial phases to 18 A Ê resolution were derived from a hollow spherical model of 192 A Ê outer radius and 139 A Ê inner radius, ®lled with uniform electron density. Radii of the model were determined by maximizing the correlation of the model-based calculated data with the low-resolution X-ray diffraction and solutionscattering data. Phases were re®ned by 60-fold noncrystallographic electron-density averaging and extended in small steps to a resolution of 5 A Ê . The phases obtained represented a mixture of four different phase sets, each consistent with the icosahedral symmetry constraints. The resulting electron density was not interpretable. A difference Fourier map computed with the native and an isomorphous heavyatom derivative data sets and phases re®ned by realspace averaging was interpretable only if data within the 10 A Ê resolution shell were used. Maps calculated with data signi®cantly higher than 10 A Ê resolution failed to display a constellation of heavy-atom sites consistent with the T = 4 icosahedral symmetry. Attempts to extend the phases beyond 10 A Ê resolution, starting with either phases based on a model or single isomorphous replacement, were unsuccessful. Successful phase extension was achieved by computing the phases for the higher resolution re¯ections from a partial atomic model (poly gly) built into the averaged 10 A Ê electron-density map. Phases from this model served as the starting point for n.c.s. phase re®nement and extension to slightly higher resolution. The atomic model was improved at each extension interval and these phases were used for the subsequent phase calculation and extension. The entire polypeptide backbone corresponding to the N3V structure was built into the map at 4 A Ê . The same procedure for phase re®nement was used to extend the phases to 2.8 A Ê in small increments of resolution. The overall molecular averaging R factor and correlation coef®cient at 2.8 A Ê resolution were 18.4% and 0.87, respectively.

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“…The puri®cation of N3V has been described previously (Hendry et al, 1985). N3V was crystallized using the sitting-drop method of vapor diffusion.…”

Section: Crystallizationmentioning

confidence: 99%

“…N3V is a spherical positive-sense single-stranded RNA virus that infects the South African pine emperor moth (Hendry et al, 1985). The icosahedral shells are 410 A Ê in diameter and consist of 240 copies of chemically identical subunits arranged in a T = 4 quasisymmetric lattice (Johnson et al, 1994;Munshi et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Structure Determination of Nudaurelia capensis ω Virus

Munshi

Liljas

Johnson

1998

Acta Crystallogr D Biol Cryst

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“…Tetravirus particles consist of one (genus Betatetravirus) or two (genus Omegatetravirus) positive-sense, single-stranded genomic RNAs encapsidated in a non-enveloped capsid of approximately 40 nm in diameter, with T54 icosahedral symmetry. The genus Omegatetravirus contains the type virus Nudaurelia capensis v virus (NvV), Helicoverpa armigera stunt virus (HaSV) and Dendrolimus punctatus virus (DpTV) (Hendry et al, 1985;Hanzlik et al, 1993;Yi et al, 2005). Omegatetravirus capsids encapsidate two genomic RNAs ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Subcellular localization and live-cell imaging of the Helicoverpa armigera stunt virus replicase in mammalian and Spodoptera frugiperda cells

Short

Knox

Dorrington

2010

Journal of General Virology

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“…The purification of virus has been described (Hendry, Hodgson, Clark & Newman, 1985); yields of 0.4 mg of virus per gram of larvae tissue are typical. The virus is purified on a 40% caesium chloride gradient using a 50 mM tris-HCl buffer at pH 7.5 and then pelleted and resuspended in 0-07 M sodium acetate buffer at pH 5.0 just prior to crystallization.…”

Section: Virus Productionmentioning

confidence: 99%

“…Nudaurelia capensis w virus (NwV) is a spherical RNA virus that was first isolated from larvae of the pine emperor moth (Hendry, Hodgson, Clark & Newman, 1985). The virus has been isolated only from larvae infected in the wild and it has not been successfully propagated in insect cell lines.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and preliminary structure analysis of an insect virus with T=4 quasi-symmetry: Nudaurelia capensis ω virus

Cavarelli¹,

Bomu²,

Liljas³

et al. 1991

Acta Crystallogr Sect B

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We report the crystallization of Nudaurelia capens& w virus, a pathogen of the pine emperor moth. The icosahedral particle has T= 4 quasi-equivalent symmetry and is approximately 410 A in diameter. Triclinic crystals (a = 414-0, b = 410.7, c = 420.1 A, re = 59.1,/3 = 58"9, y = 64-0 °) diffracting X-rays to 2-7 A resolution have been analyzed using a partial data set collected at high resolution (2-7 A) using conventional oscillation photography and a more complete data set collected at low resolution (50-9 A) using a Siemens area detector. The pseudo-rhombohedral symmetry of the crystals created significant problems in processing the unaligned oscillation photographs. Successful processing of the films depended on the

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Small RNA Viruses Co-infecting the Pine Emperor Moth (Nudaurelia cytherea capensis)

Cited by 15 publications

References 13 publications

Structure Determination of Nudaurelia capensis ω Virus

Structure Determination of Nudaurelia capensis ω Virus

Subcellular localization and live-cell imaging of the Helicoverpa armigera stunt virus replicase in mammalian and Spodoptera frugiperda cells

Crystallization and preliminary structure analysis of an insect virus with T=4 quasi-symmetry: Nudaurelia capensis ω virus

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