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Elucidation of the viral disassembly switch of tobacco mosaic virus
Author(s) -
Weis Felix,
Beckers Maximilian,
Hocht Iris,
Sachse Carsten
Publication year - 2019
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201948451
Subject(s) - physics , library science , biology , computer science
Stable capsid structures of viruses protect viral RNA while they also require controlled disassembly for releasing the viral genome in the host cell. A detailed understanding of viral disassembly processes and the involved structural switches is still lacking. This process has been extensively studied using tobacco mosaic virus ( TMV ), and carboxylate interactions are assumed to play a critical part in this process. Here, we present two cryo‐ EM structures of the helical TMV assembly at 2.0 and 1.9 Å resolution in conditions of high Ca 2+ concentration at low pH and in water. Based on our atomic models, we identify the conformational details of the disassembly switch mechanism: In high Ca 2+ /acidic pH environment, the virion is stabilized between neighboring subunits through carboxyl groups E95 and E97 in close proximity to a Ca 2+ binding site that is shared between two subunits. Upon increase in pH and lower Ca 2+ levels, mutual repulsion of the E95/E97 pair and Ca 2+ removal destabilize the network of interactions between adjacent subunits at lower radius and release the switch for viral disassembly.