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- EMDB-42628: Structure of the insect gustatory receptor Gr9 from Bombyx mori -
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Open data
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Basic information
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Title | Structure of the insect gustatory receptor Gr9 from Bombyx mori | |||||||||
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![]() | Gustatory receptor / Ion channel / Sugar-binding / Fructose / TRANSPORT PROTEIN | |||||||||
Function / homology | ![]() detection of chemical stimulus involved in sensory perception of sweet taste / ionotropic taste receptor activity / male courtship behavior / chemosensory behavior / ligand-gated monoatomic cation channel activity / monoatomic cation transmembrane transport / axon / neuronal cell body / dendrite / signal transduction / plasma membrane Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.9 Å | |||||||||
![]() | Gomes JV / Butterwick JA | |||||||||
Funding support | 1 items
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![]() | ![]() Title: The molecular basis of sugar detection by an insect taste receptor. Authors: João Victor Gomes / Shivinder Singh-Bhagania / Matthew Cenci / Carlos Chacon Cordon / Manjodh Singh / Joel A Butterwick / ![]() Abstract: Animals crave sugars because of their energy potential and the pleasurable sensation of tasting sweetness. Yet all sugars are not metabolically equivalent, requiring mechanisms to detect and ...Animals crave sugars because of their energy potential and the pleasurable sensation of tasting sweetness. Yet all sugars are not metabolically equivalent, requiring mechanisms to detect and differentiate between chemically similar sweet substances. Insects use a family of ionotropic gustatory receptors to discriminate sugars, each of which is selectively activated by specific sweet molecules. Here, to gain insight into the molecular basis of sugar selectivity, we determined structures of Gr9, a gustatory receptor from the silkworm Bombyx mori (BmGr9), in the absence and presence of its sole activating ligand, D-fructose. These structures, along with structure-guided mutagenesis and functional assays, illustrate how D-fructose is enveloped by a ligand-binding pocket that precisely matches the overall shape and pattern of chemical groups in D-fructose. However, our computational docking and experimental binding assays revealed that other sugars also bind BmGr9, yet they are unable to activate the receptor. We determined the structure of BmGr9 in complex with one such non-activating sugar, L-sorbose. Although both sugars bind a similar position, only D-fructose is capable of engaging a bridge of two conserved aromatic residues that connects the pocket to the pore helix, inducing a conformational change that allows the ion-conducting pore to open. Thus, chemical specificity does not depend solely on the selectivity of the ligand-binding pocket, but it is an emergent property arising from a combination of receptor-ligand interactions and allosteric coupling. Our results support a model whereby coarse receptor tuning is derived from the size and chemical characteristics of the pocket, whereas fine-tuning of receptor activation is achieved through the selective engagement of an allosteric pathway that regulates ion conduction. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 203.8 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 13.6 KB 13.6 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 12.6 KB | Display | ![]() |
Images | ![]() | 170.3 KB | ||
Filedesc metadata | ![]() | 5.4 KB | ||
Others | ![]() ![]() | 200.1 MB 200.1 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8uvtMC ![]() 8uvuC ![]() 8vv3C C: citing same article ( M: atomic model generated by this map |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Map
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Voxel size | X=Y=Z: 1.068 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #2
File | emd_42628_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #1
File | emd_42628_half_map_2.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
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Sample components
-Entire : Homotetramer of Gr9 in the absence of ligand
Entire | Name: Homotetramer of Gr9 in the absence of ligand |
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Components |
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-Supramolecule #1: Homotetramer of Gr9 in the absence of ligand
Supramolecule | Name: Homotetramer of Gr9 in the absence of ligand / type: complex / ID: 1 / Parent: 0 / Macromolecule list: all |
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Source (natural) | Organism: ![]() ![]() |
-Macromolecule #1: Gustatory receptor
Macromolecule | Name: Gustatory receptor / type: protein_or_peptide / ID: 1 / Number of copies: 4 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 50.67707 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: GPGRAPPSPD LRADEPKTPC LVGGAHAFIL KISSFCGLAP LRFEPRSQEY AVTISKGKCF YSYILVTFLV ICTIYGLVAE IGVGVEKSV RMSSRMSQVV SACDILVVAV TAGVGVYGAP ARMRTMLSYM ENIVAVDREL GRHHSAATER KLCALLLLIL L SFTILLVD ...String: GPGRAPPSPD LRADEPKTPC LVGGAHAFIL KISSFCGLAP LRFEPRSQEY AVTISKGKCF YSYILVTFLV ICTIYGLVAE IGVGVEKSV RMSSRMSQVV SACDILVVAV TAGVGVYGAP ARMRTMLSYM ENIVAVDREL GRHHSAATER KLCALLLLIL L SFTILLVD DFCFYAMQAG KTGRQWEIVT NYAGFYFLWY IVMVLELQFA FTALSLRARL KLFNEALNVT ASQVCKPVKK PK NSQLSVY ATSVRPVSCK RENVIVETIR VRDKDDAFVM MKTADGVPCL QVPPCEAVGR LSRMRCTLCE VTRHIADGYG LPL VIILMS TLLHLIVTPY FLIMEIIVST HRLHFLVLQF LWCTTHLIRM LVVVEPCHYT IREGKRTEDI LCRLMTLAPH GGVL SSRLE VLSRLLMLQN ISYSPLGMCT LDRPLMVTVL GAVTTYLVIL IQFQRYDS UniProtKB: Gustatory receptor |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 7.5 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 30.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.0 µm / Nominal defocus min: 0.8 µm |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |