Journal: Scientific Reports
Article Title: Dual role of the colonization factor CD2831 in Clostridium difficile pathogenesis
Figure Lengend Snippet: Binding of recombinant CD2831 full-length protein and subdomains to collagen. ( A ) Schematic representation of CD2831 domains organization displays the Leader Peptide at the N-terminus (orange) followed by a Short Repeat Region (yellow) in which repeated amino acids sequences are marked in bold, two collagen-binding domains (blue) and a Proline-rich region (green) recognized by the protease ZmpI/PPEP-1 that cleaves within the seven NPP amino acids sequences of the domain. The charged tail and the hydrophobic domain are present at the C-terminus (red). The protein is cleaved between the threonyl and glycil residues of the PPKTG motif and transferred to the cell-wall peptidoglycan by the Sortase B enzyme. Blue, black and grey lines indicate the length of recombinant CD2831 subdomains compared to the full-length. ( B ) Immunofluorescence of 1 µM of CD2831 (green) binding to collagen (red) produced by IMR90 cells. Collagen staining results from a mix of antibodies against collagen types I, III and V in a 1:1:1 ratio. Binding of the proteins was detected by using rabbit anti-CD2831 serum and secondary Alexa Fluor-conjugated antibodies. ( C ) Human fibroblasts IMR90 were cultured into collagen I-coated 96 well plates for three days after seeding. Cells were then incubated with serially diluted recombinant CD2831 proteins ranging from 0.08 to 10 µM. Binding of CD2831 was detected as above and quantified with a microplate fluorescence reader. ( D ) ELISA plates were coated with 10 μg/ml of purified collagens and incubated with serially diluted recombinant CD2831 proteins ranging from 15 nM to 2 µM. Binding of the proteins was detected using rabbit anti-CD2831 serum, followed by HRP-conjugated-secondary antibody. CWP25 protein was used as negative control. CD2831 CBD1 and CD2831 CBD2 represent the previously described subdomains 1 and 2.
Article Snippet: After blocking with PBS containing 0.05% Tween-20 (PBS-T) and 10% (w/v) milk (Sigma, USA), proteins were detected with rabbit anti-CD2831 serum diluted 1:1000 for 1 hour at RT, followed by the HRP-conjugated secondary antibodies (Dako, Denmark) diluted 1:2000 for 1 hour at RT.
Techniques: Binding Assay, Recombinant, Immunofluorescence, Produced, Staining, Cell Culture, Incubation, Fluorescence, Enzyme-linked Immunosorbent Assay, Purification, Negative Control