Genetic Incorporation of Fluorescent Amino Acid into Fatty Acid Binding Protein for Fatty Acid Detection

Fatty acids play critical roles in biological processes, such as energy storage, metabolism, signal transduction, and immune regulation. Therefore, it is necessary to develop in-vitro fluorescent sensors to detect free fatty acids. By genetically incorporating a synthetic fluorescent amino acid (L-(7-hydroxycoumarin-4-yl) ethylglycine, Cou) into fatty acid-binding protein (FABP), we obtained a fluorescent sensor that has a turn-on signal in the presence of the fatty acids. Its response to medium-chain and long-chain fatty acids can be increased by 5.8-fold within several minutes, highlighting its potential applications in fatty acids-related biological processes. Our newly developed fatty acid detection system based on genetic expansion technology has extended the molecular toolboxes available for important biological molecular analysis.