Ribonucleic acid and protein synthesis in a mutant of Bacillus subtilis defective in potassium retention.

A mutant of Bacillus subtilis 168 (strain 168 KL), which had lost its normal capacity to accumulate K(+), was used to explore the interrelationship between protein and ribonucleic acid (RNA) synthesis. In contrast to the wild type, the growth rate of strain 168 KL was markedly dependent on the K(+) concentration in the medium. K(+) uptake in the mutant strain was identical to that in the parent, but the mutant was unable to retain and accumulate K(+). Protein synthesis was markedly dependent on the K(+) concentration in the medium, whereas RNA synthesis was relatively unaffected by changes in the level of K(+). Most of the RNA synthesized during K(+) depletion was ribosomal RNA; it appeared in crude extracts in the form of ribonucleoproteins particles with sedimentation values between 4S and 30S. These particles were converted into mature ribosomes when growth was allowed to resume by the addition of K(+). Simultaneous synthesis of RNA and protein was necessary for the quantitative conversion of the ribonucleoprotein particles into ribosomes. During recovery from K(+) depletion, ribosomal protein was synthesized in preference to the other proteins of the cell.