Formation of artificial top component from brome mosaic virus at high salt concentrations

Abstract

In both 1.5 M NaCl and 1 M CaCl 2, brome mosaic virus (BMV) particles are unaffected at low pH but are degraded above a well defined pH value. The degradation into protein subunits and RNA occurs in two steps in both NaCl and CaCl 2. First, the RNA is released without collapse of the protein shell: the products obtained are RNA and artificial top component (ATC); in a second step, the ATC formed undergoes degradation into protein subunits upon further pH rise. The main difference between the action of 1 M CaCl 2 and 1.5 M NaCl is that, with CaCl 2, no intermediates of degradation were found between virus and ATC, while in NaCl, some particles underwent progressive degradation, yielding intermediate forms together with reassociation products and contaminated protein subunits.