Toxic Effects of Some Heavy Metals on the Structure and Stability of the Recombinant Human Fgfr2b Kinase Domain Publisher



Toudehrousta M ; Ilghari D ; Siratisabet M ; Piri H ; Katfayazi R ; Gheibi N ; Khoei SG ; Gheibi N
Source: Archives of Razi Institute Published:2026

Abstract

Introduction: Fibroblast growth factor receptor type II (FGFR2b) is crucial in mediating cellular signal transduction and controlling vital biological processes such as cell growth and differentiation. The disruption or impairment of signaling pathways mediated by this particular receptor has been closely associated with the pathophysiology of various human malignancies, including breast cancer, ovarian cancer, and endometrial cancer. It has been observed that toxic heavy metals, such as lead, cadmium, and aluminum, exert their detrimental effects primarily through the alteration of established signaling pathways within the cellular environment. The primary objective of this research endeavor is to conduct a comprehensive investigation into the effects of the heavy metals lead (Pb2+), cadmium (Cd2+), and aluminum (Al3+) on both the structural integrity and stability of recombinant FGFR2b. Materials & Methods: Recombinant FGFR2b kinase domain was expressed in Escherichia coli BL21 (DE3) cells and purified using Ni²⁺-NTA affinity chromatography. Protein integrity and activity were confirmed by PAGE analysis. Structural and stability changes of FGFR2b in the presence of Pb²⁺, Cd²⁺, and Al³⁺ were evaluated using intrinsic fluorescence spectroscopy and chemical denaturation with guanidine hydrochloride. Secondary structure alterations were assessed by farUV circular dichroism (CD) spectroscopy, and metal–protein interactions were further analyzed using Fourier transform infrared (FTIR) spectroscopy. Results: The analysis of intrinsic fluorescence emission and CD spectra of FGFR2b, when exposed to varying concentrations of these heavy toxic metals, indicated a gradual series of structural fluctuations that corresponded with the increased concentrations of the metals present. Furthermore, the findings from fluorescence and FTIR analysis of the protein structure demonstrated that the influence exerted by Pb2+ at concentrations of 100 and 500 µM was significantly more pronounced and impactful than the effects produced by the other two metals under investigation. The structure and stability of FGFR2b as a key receptor in cellular signal transduction were reduced by Pb2+. Conclusion: These results shed light on the effects of toxic heavy metals on biological functions of the cells via a change in their signaling pathways. © 2026 The Author(s);.