Deciphering the allosteric dynamics of GPR120-fatty acid interactions within a bilayer nanogold electrochemical receptor biosensor: the impact of replacing tryptophan 198 with proline
Wei Xu, Dan Meng, Ming Li, Qingwei Song, Wenling Wu, Yimeng Bi, Chenyu Xu, Yifei Zhang, Dingqiang Lu
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引用次数: 0
Abstract
GPR120 is a free fatty acid receptor capable of signalling excess fatty acids. GPR120 can be activated by various types of free fatty acids, causing intracellular signal transduction and exerting energy regulation, immune homeostasis, and neuronal functions. It has been suggested that Trp198 may be an important residue in the recognition and activation of GPR120 by fatty acid ligands, but direct experimental evidence is lacking. In this study, a GPR120-based bilayer gold nanoparticle biosensor (Trp198→Pro) was constructed by genetically manipulating Trp198 on GPR120 by replacing it with proline for the determination of linkage variability between 14 naturally occurring fatty acid ligands and mutant receptors. The results showed that both before and after amino acid substitution the GPR120 bilayer nanogold receptor sensor responded to all 14 natural fatty acid ligands. And the linkage transformation constants of crotonic acid, dodecanoic acid, oleic acid, linoleic acid, α-linolenic acid, and DHA decreased after Trp198 was replaced by Pro. To further reveal its molecular recognition mechanism, molecular simulation docking experiments were performed on GPR120 and 14 fatty acid ligand compounds before and after amino acid substitutions, respectively. The results showed that before and after the amino acid substitutions, the binding conformational affinity values of GPR120 docked with the ligands were negative, implying that these fatty acid ligands can spontaneously bind to the active pocket of GPR120 without absorbing external energy. Upon replacement of Trp198 by Pro, the active pocket of GPR120 at the optimal docking site with the fatty acid ligand is altered, leading to changes in the amino acid residues that exert the interaction. The above results demonstrate that Trp198 indeed plays an important role in the recognition of fatty acid ligands on GPR120. The present study provides direct quantitative evidence for the roles played by different amino acid residues in receptor-ligand recognition and interaction. At the same time, it provides new ideas for the study of other receptor-ligand-linked metastable mechanisms and kinetic laws.
期刊介绍：
Biomedical Microdevices: BioMEMS and Biomedical Nanotechnology is an interdisciplinary periodical devoted to all aspects of research in the medical diagnostic and therapeutic applications of Micro-Electro-Mechanical Systems (BioMEMS) and nanotechnology for medicine and biology.
General subjects of interest include the design, characterization, testing, modeling and clinical validation of microfabricated systems, and their integration on-chip and in larger functional units. The specific interests of the Journal include systems for neural stimulation and recording, bioseparation technologies such as nanofilters and electrophoretic equipment, miniaturized analytic and DNA identification systems, biosensors, and micro/nanotechnologies for cell and tissue research, tissue engineering, cell transplantation, and the controlled release of drugs and biological molecules.
Contributions reporting on fundamental and applied investigations of the material science, biochemistry, and physics of biomedical microdevices and nanotechnology are encouraged. A non-exhaustive list of fields of interest includes: nanoparticle synthesis, characterization, and validation of therapeutic or imaging efficacy in animal models; biocompatibility; biochemical modification of microfabricated devices, with reference to non-specific protein adsorption, and the active immobilization and patterning of proteins on micro/nanofabricated surfaces; the dynamics of fluids in micro-and-nano-fabricated channels; the electromechanical and structural response of micro/nanofabricated systems; the interactions of microdevices with cells and tissues, including biocompatibility and biodegradation studies; variations in the characteristics of the systems as a function of the micro/nanofabrication parameters.
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