Chromatographic characterization of the fusion protein SARS-CoV-2 S protein (RBD)-hFc

ABSTRACT

At the Center of Molecular Immunology (Havana, Cuba), the fusion protein SARS-CoV-2 S protein (RBD)-hFc was synthesized linking the receptor-binding domain (RBD) of the SARS-CoV-2 virus and the crystallizable fragment of a human immunoglobulin. This fusion protein was used in the construction of a diagnostic device for COVID-19 called UMELISA SARS-CoV-2-IgG. Given the relevance of this protein, the characterization of three batches (A1, A2 and A3) was carried out. The molecular weight of the protein was determined to be 120 kDa, using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Its isoelectric point was estimated between 8.3 and 9 by isoelectric focusing. The molecular integrity was evaluated by size exclusion liquid chromatography and SDS-PAGE after one year of the production of the protein;the presence of aggregates and fragments was detected. Batches A1 and A2 have a purity percentage higher than 95% and they can be used for the construction of new diagnostic devices.