Conformational states of cowpea chlorotic mottle virus ribonucleic acid components.

The conditions determining conformational changes in the four ribonucleic acid components of cowpea chlorotic mottle virus have been studied. All four components have at least two electrophoretically separable conformers, the occurrence of which can be regulated by both monovalent and polyvalent cations. This phenomenon also occurs, in a much less striking way, in the ribonucleic acids of the two other members of the bromovirus group, brome mosaic virus and broad bean mottle virus. Although specific in some respects, these changes have much in common with effects which have been observed in tRNAs, 55 RNAs and rRNAs. A provisional interpretation of the conformational behaviour of the viral RNAs is given in terms which have been proposed for certain tRNAs which have been studied in great detail.