Figure 3.

Structural and functional characterization of HR2-MPER derived peptide IPB19. The α-helicity (A) and thermostability (B) of IPB19 alone or in complex with an HR1-derived target mimic peptide N52 as well as the α-helicity (C) and thermostability (D) of C-terminally truncated IPB19 peptides complexed with N52 were determined by CD spectroscopy, with the final concentration of each peptide being 10 μM. The inhibitory activities of IPB19 and its truncated versions on S protein-mediated cell-cell fusion (E) and pseudovirus infection in 293T/ACE2 cells (F) were determined by DSP-based fusion assay and single-cycle infection assay, respectively. The CD experiment was performed two times and obtained consistent results and representative data are shown. The antiviral experiments were repeated three times, and data are expressed as the means ± SD.