summary

The ability to detect food at a molecular level is crucial for identifying high-quality sources of nutrition. Humans use canonical G protein–coupled receptors for taste, but insects are known to have distantly related gustatory receptors that function as ligand-gated ion channels. Ma et al. determined the cryo–electron microscopy structures of two gustatory receptors from the fruit fly Drosophila that bind and respond to either monosaccharides or disaccharides, as confirmed by accompanying electrophysiology measurements. The structures revealed a tetrameric ion channel with a sugar-binding site near the extracellular face in a deep, hydrophilic pocket. A mutant with constitutive activity enabled visualization of an open state of one of the channels with a wide pore consistent with nonselective cation conduction. —Michael A. Funk

原文链接：Structural basis for sugar perception by Drosophila gustatory receptors | Science