Journal: The Journal of Biological Chemistry
Article Title: Cleavage at the nsp5–nsp6 site of SARS-CoV-2 main protease intermediate precursor is faster from a monomer than a dimer form
doi: 10.1016/j.jbc.2026.111395
Figure Lengend Snippet: Time course of the processing of MPro precursors at its termini by MPro WT and characterization of the products by SDS-PAGE and SEC–MALS. A , schematic showing the precursor and products that result from cleavage by MPro WT . B and C , time course of the processing of precursors (50 μM) by MPro WT (1 μM). Samples (5 μg/lane) were analyzed by SDS-PAGE. D , SDS-PAGE of flow-through (FT) and bound (B) fractions (3 μg/lane) following nickel affinity chromatography of digest like that shown in panel ( B , 21 h). S and P refer to control lanes (2 μg/lane), Precursor C145A and mature MPro C145A , respectively. E – J , characterization of the precursor and products by SEC–MALS analyses. E , precursor C145A . F , products of the digest as shown in panel ( B , lane 21 h) of Precursor C145A (77 μM) incubated with MPro WT (1 μM). G and H , bound ( B ) and FT fractions derived from panel ( D ) corresponding to MPro C145A-IP and MBP product peaks, respectively. I , a low injection concentration of the MPro C145A-IP product. J , a low injection concentration of mature MPro C145A . D and M in parentheses refer to the predominantly dimer and monomer species, respectively, at the estimated concentration indicated below the molecular mass. M and kDa denote molecular weight markers and kilodaltons, respectively. Black circles indicate the molecular mass across the peak slice. IP, intermediate precursor; MPro, main protease; MPro WT , mature WT MPro; SEC–MALS, size-exclusion chromatography with multiangle light scattering.
Article Snippet: Proteins were fractionated by analytical SEC with in-line MALS (DAWN Heleos-II; Wyatt Technology, Inc), refractive index (Optilab T-Rex; Wyatt Technology, Inc), and UV (Waters 2487; Waters Corporation) detectors.
Techniques: SDS Page, Affinity Chromatography, Control, Incubation, Derivative Assay, Injection, Concentration Assay, Molecular Weight, Size-exclusion Chromatography, Multi-Angle Light Scattering