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Figure 1 | Veterinary Research

Figure 1

From: Foot-and-mouth disease virus-like particles produced by a SUMO fusion protein system in Escherichia coli induce potent protective immune responses in guinea pigs, swine and cattle

Figure 1

Expression and assembly of purified FMDV capsid proteins. (A) SDS-PAGE (left panel, lanes M, 1–4) and Western blot (right panel, lanes 5–8) analysis of the purified capsid protein complexes without Ulp1 protease treatment, including the SUMO-tagged FMDV VP3 protein expressed individually (lanes 1 and 8), the SUMO-tagged FMDV VP1 protein expressed individually (lanes 2 and 7), the SUMO-tagged FMDV VP0 protein expressed individually (lanes 3 and 6) and the three SUMO-tagged protein complex simultaneously expressed (lanes 4 and 5). (B) SDS-PAGE (lane 1) and Western blot (lane 2) analysis of the purified three SUMO-tagged protein complex after protease digestion and the second affinity chromatography. (C) Purification and analysis of FMD VLP by sucrose gradient ultracentrifugation. The purified three capsid proteins were loaded onto a 10%–30% (w/v) sucrose gradient. After centrifugation, 20 fractions were collected and measured at 280 nm using UA-Visible Spectrophotometer BioMate 3S (ThermoFisher Scientific Inc. USA) and the quantity of capsid proteins in each fraction was determined and plotted. (D) Negative staining electron microscopy of FMD VLP containing purified VP0, VP3 and VP1. Scale bar, 100 nm.

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