8VC2

CryoEM structure of insect gustatory receptor BmGr9 in the presence of fructose

Summary for 8VC2

• Entry DOI: 10.2210/pdb8vc2/pdb
• EMDB information: 43130
• Descriptor: Gustatory receptor, (7R,17E,20E)-4-HYDROXY-N,N,N-TRIMETHYL-9-OXO-7-[(PALMITOYLOXY)METHYL]-3,5,8-TRIOXA-4-PHOSPHAHEXACOSA-17,20-DIEN-1-AMINIUM 4-OXIDE (2 entities in total)
• Functional Keywords: gustatory receptor, homotetramer, ligand-gated ion channel, seven transmembrane, membrane protein
• Biological source: Bombyx mori (domestic silkworm)
• Total number of polymer chains: 4
• Total formula weight: 221325.55

Authors

Frank, H.M.,Walsh Jr., R.M.,Garrity, P.A.,Gaudet, R. (deposition date: 2023-12-13, release date: 2024-01-10, Last modification date: 2024-12-18)

Primary citation

Frank, H.M.,Walujkar, S.,Walsh Jr., R.M.,Laursen, W.J.,Theobald, D.L.,Garrity, P.A.,Gaudet, R.
Structural basis of ligand specificity and channel activation in an insect gustatory receptor.
Cell Rep, 43:114035-114035, 2024

PubMed Abstract: Gustatory receptors (GRs) are critical for insect chemosensation and are potential targets for controlling pests and disease vectors, making their structural investigation a vital step toward such applications. We present structures of Bombyx mori Gr9 (BmGr9), a fructose-gated cation channel, in agonist-free and fructose-bound states. BmGr9 forms a tetramer similar to distantly related insect odorant receptors (ORs). Upon fructose binding, BmGr9's channel gate opens through helix S7b movements. In contrast to ORs, BmGr9's ligand-binding pocket, shaped by a kinked helix S4 and a shorter extracellular S3-S4 loop, is larger and solvent accessible in both agonist-free and fructose-bound states. Also, unlike ORs, fructose binding by BmGr9 involves helix S5 and a pocket lined with aromatic and polar residues. Structure-based sequence alignments reveal distinct patterns of ligand-binding pocket residue conservation in GR subfamilies associated with different ligand classes. These data provide insight into the molecular basis of GR ligand specificity and function.

PubMed: 38573859
DOI: 10.1016/j.celrep.2024.114035

Experimental method

ELECTRON MICROSCOPY (3.98 Å)