Figure 1.

The C7 and clusterin association was confirmed with a native-restricted anti-C7 mAb. (A) The M7-HB2H mAb binding target is located in the C-terminal domains (highlighted in grey) of C7. These domains participate in the formation of the MAC via interaction with the C345C domain of C5, hence, the M7-HB2H antibody would likely bind to an exposed epitope in the native form of C7 (i.e. C7 that is not involved in the assembly of the MAC). The C7 gene contains 18 exons, each exon codes for a specific region of the C7 domain, which corresponds to the exon coding region displayed above. The boundary phase refers to the phase of the corresponding intron. (B) C7 purified from NHS-BioIVT with anti-C7 mAb, M7-HB2H, was separated by SDS-PAGE under non-reducing conditions and the immunoblot was probed with M7-HB2H. Protein composition of the bands visualized in (B) was analzyed by mass spectrometry and protein abundance was quantified for the (C) 100 kDa band and the (D) 75 kDa band. (E) The C7 aa residues detected in the 75 kDa band (3B) are in bold and underlined, along with an illustration of the screened residues in the C7 polypeptide chain highlighted in grey. The screened aa residues are 47% of the total C7 polypeptide chain. Black arrows indicate the exon/intron boundaries. Western blot (B) is representative of at least three independent experiments. Images were taken using Proxima C16 Phi. Figure (A) modified from Massri et al., 2022 (18).