Metal content of "soluble"-fraction ribonucleic acids.

Recently there have been a number of reports suggesting the possible importance of metals in ribonucleic acid. Wacker and Vallee (1) have reported the presence of chromium, iron, manganese, nickel, zinc, and other metals in various ribonucleic acid preparations, and have suggested that “metals may bear a functional relationship to protein synthesis and the transmission of genetic information.” Fuwa et al. (2) have described the effect of metal ions on the absorbancies of RNA preparations. Various workers have studied the stabilizing effect of metal ions on the infectivity of isolated tobacco mosaic virus RNA, and it is reported (3) that nickel ions are particularly effective. Loring et al. (4) have reported that the infectivity of isolated tobacco mosaic virus RNA parallels its iron content. Haschemeyer et al. (5) have reported that metal ions affect the physical properties of tobacco mosaic virus RNA, but they found that the metal ions did not alter infectivity. The amino acid acceptor RNAs obtained from the “soluble” fraction of cells are particularly suitable for studies of metal content. These RNAs have relatively low molecular weights (6), and the presence of as little as one atom of a metal per molecule of RNA would require over 0.1% of the metal in the RNA, an amount that should be detected readily. The availability of assays for the activity of these RNAs makes possible the correlation of metal content with activity.