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Updated: Jan 13, 2026

DNA-affinity-purified Chip DAP-chip Method to Determine Gene Targets for Bacterial Two component Regulatory Systems

DNA-affinity-purified Chip DAP-chip Method to Determine Gene Targets for Bacterial Two component Regulatory Systems

Published on: July 21, 2014

RelA/SpoTホモログのストリンジェント応答シグナリングにおける機構論的および進化的観点

Tatsuaki Kurata^1,2, Hiraku Takada^2,3

¹RNA Systems Biochemistry Laboratory, RIKEN Pioneering Research Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.

Bioscience, biotechnology, and biochemistry

|January 9, 2026

Abstract:

The stringent response is a conserved stress‑adaptation programme in bacteria, mediated by the alarmones (p)ppGpp that reprogramme transcription, translation and metabolism. This mini‑review surveys mechanistic, physiological and evolutionary facets of alarmone signalling across two classes of RelA/SpoT homologue (RSH) enzymes: multi domain-containing long RSHs and small alarmone synthetases/hydrolases (SAS/SAH). We first outline how activation is ribosome‑centred: in Escherichia coli, synthesis‑only RelA is activated only when bound to a starved ("hungry") ribosome, while SpoT is hydrolase‑biased; in Bacillus subtilis, a single bifunctional Rel shifts from hydrolysis- to synthesis-state when locked on a starved ribosome. Beyond (p)ppGpp, SAS enzymes diversify outputs by producing adenosine alarmones such as (p)ppApp and, in toxic SAS (toxSAS) modules, by pyrophosphorylating the tRNA 3'‑CCA end. Finally, we discuss evolutionary trajectories-from SAH-SAS operons to fused, ribosome‑regulated long RSHs-and argue that pseudo‑ZFD motifs in some toxSAS likely represent independent acquisitions.

キーワード:

(p)ppGpp 細菌タンパク質進化リボソームストリンジェント応答

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