The formation of empty shells upon pressure induced decapsidation of turnip yellow mosaic virus

Abstract

The stability of turnip yellow mosaic virus (TYMV) was investigated under pressure, using solution neutron small angle scattering. Dissociation products were characterized by analytical ultracentrifugation and electron microscopy. At pH 6.0, TYMV remained unaffected by pressure, up to 260 Megapascals (MPa), the highest pressure reached in these experiments. At pH 8.0, TYMV remained unaffected by pressure up to 160 MPa, but decapsidated irreversibly above 200 MPa, giving rise to more and more empty shells upon increasing pressure. The organization of these empty shells was similar to that of the capsid of native virions, apart from the presence of a hole corresponding to the loss of a group of 5-8 coat protein subunits, through which the RNA may have escaped. At variance with other small isometric viruses, the capsid of TYMV never dissociated under pressure into subunits or small aggregates of subunits. This exceptional behavior of TYMV is probably due to the importance of van der Waals contacts and hydrogen bonds in the stability of its capsid.

The RNA of turnip yellow mosaic virus exhibits icosahedral order

“…This is composed of native or near native protein capsids that lack RNA (Matthews, 1960). A preparation of particles identical in most respects to this top component can be made by thawing intact virions from liquid nitrogen temperatures (Kaper and Siberg, 1969) or by other means such as pH change (Keeling and Matthews, 1982) and high pressure (Leimkuhler et al, 2001) (for reviews, see references (Givord et al, 1972;Kaper, 1975;Michels et al, 1999)). These other preparations are collectively referred to as artificial top component (ATC).…”

Controlling Protein Nanocage Assembly with Hydrostatic Pressure

“…In contrast, the turnip yellow mosaic virus irreversibly decapsidates rather than dissociates under pressure, resulting in loss of RNA and formation of a holed capsid, as the subunit interface contains few pressuresensitive salt bridge and is rich in pressure-insensitive hydrogen-bonding interactions. 67 The observed difference in dissociation with temperature may also be due to a temperature-dependent ΔV effect, in which the unfolded state occupies a larger volume at higher temperature, thus disfavoring dissociation driven by an overall volume change. 68 Dissociation in this system is at least partially driven by a change in volume, so this effect could contribute to the observed disparity.…”

Bionanoparticles and their Biomedical Applications

“…The empty vesicles can be generated via high pressures [110] or deep-freeze/thaw methods [111] and these unique structures have been visualized by cryo-electron microscopy as intact particles in solution after decapsidation. The particles offer the unique opportunity to decorate the interior cavity of about 18 nm in diameter.…”