Objective  The ribavirin (RBV) single-chain antibody (scFv) gene was constructed, cloned, and physiochemically analyzed to establish a model for the detection method development and molecular modification.

  Method  Using the total RNA of the hybridoma cell line secreting RBV antibody as a template, both heavy-chain (VH) and light-chain variable (VL) regions of the antibody were amplified by RT-PCR. Then the short peptide （Gly₄Ser）₃ was employed as the splicing joint to construct the complete scFv-RBV. Bioinformatics methods were applied to predict and analyze the physiochemical properties, protein structure, and functions of the gene.

  Results  The constructed scFv-RBV encoded 240 amino acids with a relative molecular mass of 26,162.27 Da and a theoretical isoelectric point of 8.57. The secondary structure of the protein consisted of 39.17% β-sheets, 45.41% random coils, 5.42% α-helices, and 10% β-turns. In the tertiary structure, the VH and VL regions were pulled close by Linker, forming a typical pocket-like spatial configuration that conforms to the structural characteristics of a single-chain antibody. Theoretically, it could bind specifically to RBV antigens.

  Conclusion  The successfully constructed scFv-RBV in this study afforded the utilization of bioinformatics methods to predict and analyze the secondary and tertiary structures of scFv gene paving the way for further studies on the expression, purification, and directed evolution of the single-chain antibodies.