Fig. 2 | Scientific Reports

Fig. 2

From: Periodontopathogens degrade angiotensin I from the human renin–angiotensin system through surface-attached proteases

Fig. 2

Determination of the substrate specificity of PgPepO and TfPepO. (A) Peptide and protein substrates were each incubated alone (control, ctrl) and with a PepO, with wild-type (wt) and catalytically inactive ExxxA mutants serving as negative controls, at substrate: enzyme mass ratios of 100:1 (big endothelin-1), 2,000:1 (insulin B-chain), 80:1 (casein), and 200:1 (α-casein). The products obtained were analyzed by SDS-PAGE and mass spectrometry (MS). (B) Mixtures of angiotensinogen 1–14 and human big endothelin-1 (Big ET-1) incubated at 800:1 substrate: enzyme mass ratios with PepO wt, E527A (PepO), or E515A (TfPepO) mutants were separated by high-performance liquid chromatography. The substances corresponding to the peaks indicated by asterisks (*) were identified using MS (C, D) The identified mass spectrometry cleavage sites for both PepOs are marked on the primary structures of the substrates using differently colored triangles (C) and were used to create the cleavage logo with Multiple Em for Motif Elicitation (MEME) (https://meme-suite.org) (D).

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