Structural studies on tobacco streak virus coat protein: Insights into the pleomorphic nature of ilarviruses

Tobacco streak virus (TSV), the type member of Ilarvirus genus, is a major plant pathogen. TSV purified from infected plants consists of a ss-RNA genome encapsidated in spheroidal particles with diameters of 27, 30 and 33 nm constructed from multiple copies of a single species of coat protein (CP) subunits. Apart from protecting the viral genome, CPs of ilarviruses play several key roles in the life cycle of these viruses. Unlike the related bromo and cucumoviruses, ilarvirus particles are labile and pleomorphic, which has posed difficulties in their crystallization and structure determination. In the current study, a truncated TSV-CP was crystallized in two distinct forms and their structures were determined at resolutions of 2.4 angstrom and 2.1 angstrom, respectively. The core of TSV CP was found to possess the canonical beta-barrel jelly roll tertiary structure observed in several other viruses. Dimers of CP with swapped C-terminal arms (C-arm) were observed in both the crystal forms. The C-arm was found to be flexible and is likely to be responsible for the polymorphic and pleomorphic nature of TSV capsids. Consistent with this observation, mutations in the hinge region of the C-arm that reduce the flexibility resulted in the formation of more uniform particles. TSV CP was found to be structurally similar to that of Alfalfa mosaic virus (AMV) accounting for similar mechanism of genome activation in alfamo and ilar viruses. This communication represents the first report on the structure of the CP from an ilarvirus. (C) 2015 Elsevier Inc. All rights reserved.

Recovering Nussbaum's aristotelian roots

Abstract: The paper examines the relationship between Creating Capabilities and political liberalism. Originally founded on the basis of Aristotelian philosophy, the theory of ‘capabilities’ developed by Nussbaum turns to political liberalism in the mid 90’s. Throughout the article, the principles of both perspectives are depicted and contrasted, focusing on the capacity of affiliation, the concept of common good and the idea of freedom. Severine Deneulin argues that the current reality calls for the capabilities approach to be more rooted in a relational anthropology which the Aristotelian ethical tradition is more akin to. This line can be found in Nussbaum’s first approach to the theory of capabilities, where affiliation as an architectonic capability leads to the common good being the end of political action, and practical reason as an architectonic capability leads to reasoning ordered towards the achievement of the common good, to the detriment of individualism.

Altruism with Social Roots: An Emerging Literature

Revised: 2007-01.-- Published as an article in: Revista Desarrollo y Sociedad (2006), Semestre II, pp. 245-260.

Roots of prosperity: the Pacific Coast Watershed Partnership

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