Fig. 5: TcsH binding blocks the proteolytic activity of TMPRSS2.
From: Molecular basis of TMPRSS2 recognition by Paeniclostridium sordellii hemorrhagic toxin
a The top view of TMPRSS2SPD structure with the catalytic triad (H296, D345, S441) in the serine protease domain highlighted with sticks and green color. b In the TcsH-TMPRSS2 complex, CROP unit-VI covers the catalytic pocket of TMPRSS2. Loops of SR27 and SR29 stretch into the catalytic pocket and possibly block the substrate entrance. c Schematic diagram illustrating the principle of TMPRSS2 protease activity assay. TMPRSS2 cleaves at the bond after the Arginine of a fluorogenic peptide substrate Boc-QAR-AMC, releasing AMC with bright fluorescence emitted. d TcsH2210-2618 blocks the proteolytic activity of TMPRSS2ECD in a concentration-dependent manner. The relative fluorescence value (proportional to the proteolytic activity of TMPRSS2) generated from released AMC is shown in a bar chart. The concentration of the substrate, TMPRSS2ECD, and TcsH1832-2209 is 10 μM, 30 nM, and 2 μM, respectively. TcsH2210-2618 concentration gradient: 3.2 nM, 16 nM, 80 nM, 400 nM, and 2 μM. e TcsH2210-2618 mutants show the attenuated ability to block the proteolytic activity of TMPRSS2ECD. The concentrations of Boc-QAR-AMC, TMPRSS2ECD, and TcsH2210-2618 fragments are 10 μM, 30 nM, and 400 nM, respectively. In (d, e), data are shown as mean ± SD, n = 3 independent samples, two-tailed Student’s t test. Source data are provided as a Source Data file.
