A prominent feature of the stringent response is the accumulation of two unusual phosphorylated derivatives of GTP and GDP (pppGpp: 5′-triphosphate-3′-diphosphate, and ppGpp: 5′-3′-bis-diphosphate), collectively called (p) ppGpp, within a few seconds after the onset of amino-acid starvation. The synthesis of these 'alarmone'compounds is catalyzed by RelA homologues. Other features of the stringent response include inhibition ...
