Thermostability of the Foot-and-Mouth Disease Virus Capsid Is Modulated by Lethal and Viability-Restoring Compensatory Amino Acid Substitutions.

A new interesting article has been published in J Virol. 2019 May 1;93(10). pii: e02293-18. doi: 10.1128/JVI.02293-18. Print 2019 May 15. and titled:

Thermostability of the Foot-and-Mouth Disease Virus Capsid Is Modulated by Lethal and Viability-Restoring Compensatory Amino Acid Substitutions.

Authors of this article are:

López-Argüello S, Rincón V, Rodríguez-Huete A, Martínez-Salas E, Belsham GJ, Valbuena A, Mateu MG.

A summary of the article is shown below:

Infection by viruses depends on a balance between capsid stability and dynamics. This study investigated biologically and biotechnologically relevant aspects of the relationship in foot-and-mouth disease virus (FMDV) between capsid structure and thermostability and between thermostability and infectivity. In the FMDV capsid, a substantial number of amino acid side chains at the interfaces between pentameric subunits are charged at neutral pH. Here a mutational analysis revealed that the essential role for virus infection of most of the 8 tested charged groups is not related to substantial changes in capsid protein expression or processing or in capsid assembly or stability against a thermally induced dissociation into pentamers. However, the positively charged side chains of R2018 and H3141, located at the interpentamer interfaces close to the capsid 2-fold symmetry axes, were found to be critical both for virus infectivity and for keeping the capsid in a state of weak thermostability. A charge-restoring substitution (N2019H) that was repeatedly fixed during amplification of viral genomes carrying deleterious mutations reverted both the lethal and capsid-stabilizing effects of the substitution H3141A, leading to a double mutant virus with close to normal infectivity and thermolability. H3141A and other thermostabilizing substitutions had no detectable effect on capsid resistance to acid-induced dissociation into pentamers. The results suggest that FMDV infectivity requires limited local stability around the 2-fold axes at the interpentamer interfaces of the capsid. The implications for the mechanism of genome uncoating in FMDV and the development of thermostabilized vaccines against foot-and-mouth disease are discussed.IMPORTANCE This study provides novel insights into the little-known structural determinants of the balance between thermal stability and instability in the capsid of foot-and-mouth disease virus and into the relationship between capsid stability and virus infectivity. The results provide new guidelines for the development of thermostabilized empty capsid-based recombinant vaccines against foot-and-mouth disease, one of the economically most important animal diseases worldwide.Copyright © 2019 American Society for Microbiology.

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This article is a good source of information and a good way to become familiar with topics such as: capsid; foot-and-mouth disease virus; protein engineering; thermal stability; vaccine.