Among Antibody-Like Molecules, Monobodies, Able to Interact with Nucleocapsid Protein of SARS-CoV Virus, There Are Monobodies with High Affinity to Nucleocapsid Protein of SARS-CoV-2 Virus

Abstract

Seven amino acid sequences of antibody mimetics molecules, monobodies, capable of interacting with the nucleocapsid protein of the SARS-CoV virus, were taken from the literature. Nucleotide sequences of monobody genes were obtained by gene synthesis, which were expressed in E. coli and isolated using Ni-NTA chromatography. It was shown by thermophoresis that three of the seven selected antibody-like molecules can interact with high affinity (dissociation constant of tens of nM) with the nucleocapsid protein of the SARS-CoV-2 virus. For the remaining four monobodies, only low affinity binding with a dissociation constant of several μM was found.

Keywords: SARS-CoV; SARS-CoV-2; antibody-like molecules; monobody; nucleocapsid protein; thermophoresis.

Fig. 1.

Dependences of relative fluorescence (fluorescence before the start of thermophoresis was taken as 100%) 20 s after the start of thermophoresis on the concentration of Fn-N at a constant concentration of N protein (40 nM) for Fn-N with low affinity for the N protein (a) and with high affinity for the N protein (b). SEs of relative fluorescence are shown (8–12 replicates).