ABSTRACT
The outbreak of coronavirus disease (COVID-19) caused by SARS-CoV-2 virus continually lead to worldwide human infections and deaths. Currently, there is no specific viral protein-targeted therapeutics. Viral nucleocapsid protein is a potential antiviral drug target, serving multiple critical functions during the viral life cycle. However, the structural information of SARS-CoV-2 nucleocapsid protein remains unclear. Herein, we have determined the 2.7 Å crystal structure of the N-terminal RNA binding domain of SARS-CoV-2 nucleocapsid protein. Although the overall structure is similar as other reported coronavirus nucleocapsid protein N-terminal domain, the surface electrostatic potential characteristics between them are distinct. Further comparison with mild virus type HCoV-OC43 equivalent domain demonstrates a unique potential RNA binding pocket alongside the -sheet core. Complemented by binding studies, our data provide several atomic resolution features of SARS-CoV-2 nucleocapsid protein N-terminal domain, guiding the design of novel antiviral agents specific targeting to SARS-CoV-2.
ABSTRACT
Objective:To screen epitope mimics to lipoteichoic acid from a random 12-mer phage display peptide library and i-dentify the specificity of the mimotopes of LTA.Methods:The monoclonal antibody against LTA was used as a target to screen the 12-mer phage display peptide library and the specificity of phage clones were identified by sandwich ELISA.The amino acid sequences of positive phage clones were deduced from DNA sequencing.The specificity of synthetic peptide were identified by sandwich ELISA.Results:4 clones were obtained after 3 rounds of screening.Amino acid sequence analysis revealed four different types of mimotope sequence.A linear peptide (GHxDFRQxxQPS),named L2,which derived from positive sequence was synthesized.ELISA result indicates that L2 can bind to anti-LTA mAb specifically in a dose-dependent manner.Conclusion:The mimotopes of LTA were obtained by using the phage display technology.