Molecular logic of the Zur-regulated zinc deprivation response in Bacillus subtilis

作者：Shin Jung Ho; Helmann John D

来源：Nature Communications, 2016, 7(1): 12612.

DOI：10.1038/ncomms12612

Bacteria respond dynamically to the changes in zinc availability. Repression by the Bacillus subtilis transcription factor Zur requires Zn(II), which binds with negative cooperativity to two regulatory sites per dimer to form, sequentially, Zur(2): Zn-3 and Zur(2): Zn-4 forms of the repressor. Here we show that, as cells transition from zinc sufficiency to deficiency, operons regulated by Zur are derepressed in three distinct waves. The first includes the alternative RpmEB(L31*) and RpmGC(L33*) ribosomal proteins, which mobilize zinc from the ribosome, whereas the second includes the ZnuACB uptake system and the YciC metallochaperone. Finally, as zinc levels decrease further, the Zur(2): Zn-3 form loses Zn(II) leading to derepression of RpsNB(S14*) and FolE2, which allow continued ribosome assembly and folate synthesis, respectively. We infer that zinc mobilization from intracellular zinc stores takes priority over energy-dependent import, and our results link the biochemistry of zinc sensing by Zur to the molecular logic of the zinc deprivation response.

• 出版日期2016-8