RNA-dependent disassembly of Triatoma Virus (TrV) under alkaline conditions followed by native-MS and AFM

SNIJDER, J; UETRECHT, C; AGUIRRE, J; SANCHEZ- EUGENIA, R; MARTI G. A; GUERIN, D.M.A.; HECK, A; WUITE, G; ROOS, W

Simposio; Seventh International Virus Assembly Symposium; 2012

Viral RNA, besides being the carrier of the genetic information, is also essential for the structural stability of viral particles. This capsid RNA-dependent stability is strongly dependent on pH. Here we study in vitro the influence of viral RNA in the pH-dependent assembly/disassembly and stability of Triatoma Virus. TrV, which belongs to the virus family Dicistroviridae, consists on a small, non-enveloped capsid enclosing a +ssRNA genome. The studies presented here have been carried out using atomic force microscopy nanoindentation and native mass spectrometry. We show that at neutral pH the virion protein shell is stabilized by the densely packed single strand RNA. However, under increasingly alkaline conditions the RNA starts to destabilize the capsid triggering disassembly and genome release. Around pH 8 the destabilization is reversible but around pH 9 the genome is released turning the process as irreversible. On the other hand, empty capsid particles appear completely unaffected by pH, revealing that the pH-stability of TrV is strongly dependent on the interplay between RNA and protein shell.