Expression and Purification of the Recombinant Kinase Domain of FGFR2b and Study of its Structural Changes Due to the Interaction with Gallic Acid

FGFR2b plays a significant role in cell signaling pathway, regulating several key biological processes including cellular differentiation and proliferation. Genetic alterations of the tyrosine kinase domain of FGFR2b, such as point mutations, occur in breast, ovarian and prostate cancer. This study aimed to express and zepurify the human FGFR2b kinase domain and to analyze its structural changes upon interaction with Gallic acid (GA). Expression of recombinant protein was induced with 1mM IPTG at 37 ºC and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein was purified via affinity chromatography and the protein sample was dialyzed and then used to be analyzed via SDS-PAGE. Chemical denaturation and intrinsic fluorescence spectra of the purified proteins were carried out via adding different concentrations of Gallic acid. Comparison between pre- and post-induction samples via SDS-PAGE analysis showed that the expressed protein was soluble at 20 ºC. Additionally, its purity was confirmed. The intrinsic fluorescence spectra of kinase domain in the presence of Gallic acid showed an increase in fluorescence intensity and maximum emission wavelength. Regarding to the results, the recombinant kinase domain of FGFR2b (38 kDa) was expressed, solubilized and purified. Changing in tertiary structural kinase domain reflects a conformational change within the protein that is important for the biological function of FGFR2b.