Isolation, Characterization, and Molecular Modeling of a Rheumatoid Factor from a Hepatitis C Virus Infected Patient with Sjögren's Syndrome

Lee, Yu-Ching; Tsai, Keng-Chang; Leu, Sy-Jye; Wang, Tuan-Jen; Liu, Chia-Yu; Yang, Yi-Yuan

In order to comprehensively explain the interactions between an antibody and its target antigen, molecular modeling has been employed as a powerful and reliable approach for rational model prediction of an antibody-antigen complex. By analyzing and comparing the X-ray crystal structures of antibody-antigen complexes retrieved from the Protein Data Bank (PDB), many researches have demonstrated that sufficient information is available for analysis to indicate critical residues of great influence on the binding sites from antibody-antigen recognition interfaces [19] . In this study, we demonstrated that the isolated IgG RF has a better binding affinity than the existing complex generated by the IgM RF molecule. We managed to construct antibody models via homology modeling and used structural alignment and loop minimization to illustrate the possible role of somatic mutation induced in the CDR areas during the interactions. The logical and reasonable predicted results provide a probable explanation and further insights into the diversity and origin of these IgG RFs.