[Bioinformation analysis, eukaryotic expression and identification of β2m-linker 2-HLA A24]

Objective To explore the structure and function of β2 microglobulin-linker 2-human leukocyte antigen A24 (β2m-linker 2-HLA A24) by bioinformatics, and to obtain the purified protein by eukaryotic expression. Methods The physicochemical properties of β2m-linker 2-HLA A24 was predicted by ProtParam. The predicting software of phosphorylation site (NetPhos) and the predicting software of the secondary structure (SOPMA) were used to analyze the phosphorylation site and the secondary structure of the protein, respectively. And the predicting tool of modeling the proteins' structure (SWISS-MODEL) was used to model its tertiary structure. Then the recombinant plasmid of pcDNA3.4/β2m-linker 2-HLA A24-His tag was constructed and transfected into Expi293F cells. The protein of interest was purified through Ni-affinity chromatography. And the purity and properties of the protein were identified by SDS-PAGE, Western blot analysis and indirect ELISA. Results The β2m-linker 2-HLA A24 protein contained 44 phosphorylated sites. The protein was predicted to be a hydrophilic protein, of which the secondary structure mainly consists of irregular curl, and the modeling of the tertiary structure was successful. The recombinant plasmids of pcDNA3.4/β2m-linker 2-HLA A24-His tag was successfully constructed and expressed in the Expi293F cells. Conclusion The β2m-linker 2-HLA A24 protein has been successfully constructed. And bioinformatics results show that the protein has the function of binding to antigen peptides and activating T cells. It has established a foundation for activating antigen-specific CD8⁺ T cell stimulated by this protein and peptide in the subsequent experiments.