Journal: Biochimie
Article Title: Proteolytic processing and activation of gingipain zymogens secreted by T9SS of Porphyromonas gingivalis
doi: 10.1016/j.biochi.2019.06.010
Figure Lengend Snippet: (A) Inhibitors EDTA (5 mM), TLCK (5 mM), Leupeptin (5 mM) or 4,4’-Dithiodipyridine disulphide (2 mM) were added to bacterial cultures adjusted to OD600=1.5. After centrifugation, bacteria were washed once and diluted PBS-containing inhibitors and lysed by ultrasonication. ProRgpB6His present in the intracellular compartments was analyzed by Western blot with anti-RgpB. (B) ProRgpB6His in the T9SS-deficient ΔporN background was purified by affinity chromatography with 2 mM 4,4’-Dithiodipyridine disulphide added at each purification step. Final products were analyzed by SDS-PAGE, by Western blotting and by active-site labeling using the biotinylated probe BiRK. N-terminal sequences were determined by automated Edman-degradation as indicated. (C) ProRgpB6His (0.4 mg/ml) was incubated at room temperature in gingipain activity buffer supplemented with 10 mM DTT. At various times points, aliquots were removed to follow the proteolytic autoprocessing of the enzyme by SDS-PAGE and Western blotting. The active forms of processed proRgpB were identified by active-site labeling using the biotinylated probe BiRK. Mature RgpB bearing a C-terminal HisTag (lane M) was used as positive control. The incubation process was repeated in the presence of each of the three active gingipains (RgpB, HRgpA and Kgp) at a molar ratio 1:100. Incubations for 96 h in presence of TLCK were used as negative control (Ctl). (D) Alternatively, the processing in presence of active RgpB in the reduced conditions was followed by Native-PAGE electrophoresis.
Article Snippet: The membranes were then incubated with a rabbit polyconal anti-RgpB antibody, a rabbit polyclonal anti-HisTag antibody (GenScript) or a rabbit polyclonal anti-RgpBCTD antibody (custom pAb by Genscript; raised against synthetic peptide RVATAKNRMC) and with the corresponding secondary antibody (anti-rabbit IgG-peroxidase conjugate (Sigma) and anti-mouse IgG-alkaline phosphatase conjugate (Sigma)).
Techniques: Centrifugation, Bacteria, Western Blot, Purification, Affinity Chromatography, SDS Page, Labeling, Incubation, Activity Assay, Positive Control, Negative Control, Clear Native PAGE, Electrophoresis