The atomic structure of Carnation Mottle Virus capsid protein

Abstract

The structure of the Carnation Mottle Virus (CMtV) capsid protein has been determined at 3.2 A resolution by the method of molecular replacement. Three-dimensional data were collected from a small number of crystals (sp.g. I23, a = 382.6 A) using the synchrotron radiation with an image plate as detector. The coordinates of Tomato Bushy Stunt Virus (TBSV) were used as a searching model. Refinement of the coordinates of 7,479 non-hydrogen atoms performed by the program XPLOR, has led to an R-factor of 18.3%. It was found that the amino acid chain fold of capsid protein is very similar to that in other icosahedral viruses. However, there are some differences in the contact regions between protein subunits and also the lack of the beta-annulus around the 3-fold icosahedral axes. The structural and biochemical results lead us to consider an alternative assembly pathway.

Removal of Divalent Cations Induces Structural Transitions in Red Clover Necrotic Mosaic Virus , Revealing a Potential Mechanism for RNA Release

“…In addition, the loop that connects the R and S domains (the arm) is ordered in C subunits but disordered in A and B subunits. A similar structural organization was observed in Turnip crinkle virus (TCV) (50) and Carnation mottle virus (CarMV) (25), which are two other species in the Tombusviridae family and whose capsid structures have been solved to a resolution of ϳ3 Å. All three viruses share a phylogenetically related CP, produce virions with capsids possessing Tϭ3 icosahedral symmetry (9), and are ϳ350 Å in diameter.…”

“…This high degree of virion stability raises the question of how the intracellular environment triggers disassembly or minimally exposes the genome for translation. Structural analyses of several plant viruses have revealed that maintenance of a stable capsid conformation is dependent on the presence of divalent cations bound to the capsid (25,33,36). It has been a longstanding hypothesis that swelling and other conformational changes induced by ion extraction from virions are critical for a productive viral life cycle (13).…”

Imaging Plates in Synchrotron and Conventional X-Ray Crystallographic Data Collection

“…Data collection on crystals of Carnation Mottle Virus [10] illustrates very well the advantage of using slort wavelengths. Some data had previously been collected on these crystals on film with 1.488 Α radiation and under these conditions crystals could withstand only one or two exposures.…”

“…The structure was easily solved by molecular replacement and refined with 5-fold non-crystallographic symmetry restraints to an R factor of 18%. The model comprises 7 479 protein atoms [10].…”

Análisis Funcional De Proteínas Codificadas Por El Virus De La Rotura Del Color De La Flor Del Pelargonium

“…Hasta el momento se conoce con bastante detalle la estructura de los viriones formados por 5 miembros del género: el CarMV [Morgunova et al, 1994], el CPMoV [Ke et al, 2004], el HCRSV Doan et al, 2003;Cheng et al, 2009a], el MNSV [Wada et al, 2008] y el TCV [Hogle et al, 1986]. Estos estudios han permitido conocer mejor la interrelación entre las distintas subunidades de la CP e inferir la forma en la que tiene lugar el ensamblaje de las partículas [Ke et al, 2004].…”