Fig. 2: Involvement of protease DegP and DegQ in lysine decarboxylation metabolism through CadC cleavage. | Communications Biology

Fig. 2: Involvement of protease DegP and DegQ in lysine decarboxylation metabolism through CadC cleavage.

From: Molecular mechanism of proteolytic cleavage-dependent activation of CadC-mediated response to acid in E. coli

Fig. 2

a Formaldehyde cross-linking results during CadC purification. b Pattern diagram illustrating the structural domains of CadC. The N-terminal (1-107) represents the DNA-binding structural domain, 160-183 is the transmembrane structural domain, and 189-512 is the pH-signal sensing structural domain. The arrow indicates the enzyme cleavage site, with N-terminal sequencing revealing R-LPMSKS, pinpointing the cleavage site between 184R-185L. c, Lysine decarboxylation (LDC) assay assessing the decarboxylation ability of MG1655 and its mutant strains. Transcription levels of cadA (d) and cadB (e) genes in MG1655 and its mutant strains post-acid and lysine stimulation, detected by qRT-PCR. Data are mean ± SD of n = 3 biologically independent replicates. Various letters signify significant differences among samples at the same detection time, as per Duncan’s test (p < 0.05, n = 3). f, g Western blot and corresponding gray scale results of CadC in MG1655, ΔdegP: degQ, ΔdegP, ΔdegQ. Samples were stimulated under pH 5.8 and lysine conditions over 0-1 hours. DnaK served as a control for immunoblotting analysis of the total protein. The results used for MG1655 strain in Fig. 2f are consistent with Fig. 1e.

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