Characterization of a disassembly deficient mutant of cowpea chlorotic mottle virus.

摘要

A mutant of cowpea chlorotic mottle bromovirus, cpR26C (coat protein R26C), was investigated. The mutant displayed increased virion stability and was abnormal in disassembly when purified under nonreducing conditions. Reduced virions were infectiousand nonreduced virions were noninfectious. The nonreducing cpR26C mutant virions resisted disassembly in 0.5 M CaCl2, pH 7.5, swelled in neutral pH conditions (pH 7.5) and did not disassociate when the ionic strength was increased. Wild type virions orreducing cpR26C mutants completely disassociated into their components at pH 7.5 and high ionic strength (i>1). Sequence analysis of the cpR26C mutant identified a single cytosine to uracil change at position 1435 of RNA 3 (position 86 of RNA 4), which resulted in an arginine to cysteine change at position 26 of the coat protein.