SEVERAL SYMPTOM-MODULATING MUTATIONS IN THE COAT PROTEIN OF TURNIP CRINKLE CARMOVIRUS RESULT IN PARTICLES WITH ABERRANT CONFORMATIONAL PROPERTIES

Particles of several symptom-modulating TCV coat protein (CP) mutants were pretreated at pH 5.5, 7.5 or 8.5 and their conformations compared by agarose gel electrophoresis to those of wild-type particles. Parti cles of two mutants were swollen under conditions in which wild-type p articles remained contracted; particles of one mutant were contracted under conditions in which wildtype particles were swollen; a portion o f the particles of one mutant was contracted and another portion swoll en under conditions in which wild-type particles remained contracted; and particles of one mutant, that elicited wild-type symptoms, comigra ted with wild-type particles under all conditions tested. The results of in vitro translation experiments with mutant particles were essenti ally similar to those with wild-type particles, despite conformational differences at pH 5.5 and 8.5. These results suggest that more than t he swollen conformation is required for in vitro translation, and that particle conformation may play a role in symptom elicitation.