Liberation of zinc-containing L31 (RpmE) from ribosomes by its paralogous gene product, YtiA, in Bacillus subtilis.

We have found that alternative localization of two types of L31 ribosomal protein, RpmE and YtiA, is controlled by the intracellular concentration of zinc in Bacillus subtilis. The detailed mechanisms for the alternation of L31 proteins under zinc-deficient conditions were previously unknown. To obtain further information about this regulatory mechanism, we have studied the stability of RpmE in vivo and the binding affinity of these proteins to ribosomes in vitro, and we have found that liberation of RpmE from ribosomes is triggered by the expression of ytiA, which is induced by the derepression of Zur under zinc-deficient conditions.