Structural basis of ligand specificity and channel activation in an insect gustatory receptor.
Cell Rep
; 43(4): 114035, 2024 Apr 23.
Article
em En
| MEDLINE
| ID: mdl-38573859
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.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bombyx
Limite:
Animals
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article