Fig. 4: Activities of enzymes involved in the oxidative branch of the TCA cycle in the RelQ cells. | Communications Biology

Fig. 4: Activities of enzymes involved in the oxidative branch of the TCA cycle in the RelQ cells.

From: ppGpp accumulation reduces the expression of the global nitrogen homeostasis-modulating NtcA regulon by affecting 2-oxoglutarate levels

Fig. 4

a Specific activities (SA) of citrate synthase (CS), aconitase (ACN), and isocitrate dehydrogenase (ICD) in crude extracts of RelQ cells cultured for 24 h with or without IPTG; IPTG was added after 72 h of initial culture. Statistical significance between each sampling point of RelQ-ox and RelQ cells was determined using Student’s t test (**p < 0.01). All data are presented as mean ± SD (n = 3 independent biological experiments). b (Left) SDS-PAGE of purified recombinant Synpcc7942_0903 protein, indicated by an arrow. (Right) Dose-dependent effect of ppGpp on the aconitase activity of the recombinant Synpcc7942_0903 protein. Aconitase activity of the purified recombinant proteins (0.71 µM) evaluated in the presence of various concentrations of ppGpp (0.25, 0.5, 1.0, 2.5, 5, 7.5, and 10 µM) under anaerobic condition. Activity without ppGpp was set as 100%. Statistical significance among the relative activities without ppGpp and with each concentration of ppGpp was determined using the Dunnett test (*p < 0.05).

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