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Fig. 2 | Virology Journal

Fig. 2

From: Three kinds of treatment with Homoharringtonine, Hydroxychloroquine or shRNA and their combination against coronavirus PEDV in vitro

Fig. 2

Construction and antiviral activity of soluble peptide tHR2. a, The primary structure of each helix consists of heptad repeats (HRs) (abcdefg) n, in which a, d, and e are interactive sties and b, c, f, and g are solvent-accessible sites. Accordingly, the region of residues from 1263 to 1314 (52 residues) is the potential HR2 domain. The truncated HR2 (tHR2) domain contains residues 1278 to 1316 (39 residues). b, Gel-filtration analysis of combination of HR1 and tHR2 at the equimolar concentration. c, The primary structure of each α-helix consists of a heptad repeat composed of seven residues commonly denoted by (abcdefg)n, in which a, d, and e are interactive sties. Most important helix-forming residues of site a are highly conserved leucine (L) or isoleucine (I) residues; residues of sites d and e are relatively conserved. d, Circular dichroism (CD) spectra analysis. A typical α-helix secondary structure for mixing HR1 and tHR2 was showed. HR1, tHR2 and mixture of both were diluted in PBS for indicated concentrations. The wavelength-dependence of molar ellipticity is monitored at 25 °C as the average of eight scans in a spectropolarimeter. e and f, Vero cells were treated with scramble (NC) or tHR2 peptides at concentrations of 40 and 80 μM at the time of PEDV infection for 1 h at 37 °C, washed three times with PBS, and overlaid with DMEM-2% FBS containing tHR2. At 48 h post infection, cells were harvested, and viral proteins were detected by western blotting and viral titers were evaluated by TCID50 assay. g, Effects of tHR2 on cell viability. Cells were treated with various concentrations of tHR2 for 24 h, and cell viability was determined by MTT assay. These experiments were performed two times with three replicates in each experiment. Significance was determined by one-way analysis. Values represent means and SD. * p < 0.05 compared to PBS-treated group

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