Crystal Structures and Binding Dynamics of Odorant-Binding Protein 3 from two aphid species Megoura viciae and Nasonovia ribisnigri.
Aphids use chemical cues to locate hosts and find mates. The vetch aphid Megoura viciae feeds exclusively on the Fabaceae, whereas the currant-lettuce aphid Nasonovia ribisnigri alternates hosts between the Grossulariaceae and Asteraceae. Both species use alarm pheromones to warn of dangers. For N. ribisnigri this pheromone is a single component (E)-β-farnesene but M. viciae uses a mixture of (E)-β-farnesene, (-)-α-pinene, β-pinene, and limonene. Odorant-binding proteins (OBP) are believed to capture and transport such semiochemicals to their receptors. Here, we report the first aphid OBP crystal structures and examine their molecular interactions with the alarm pheromone components. Our study reveals some unique structural features: 1) the lack of an internal ligand binding site; 2) a striking groove in the surface of the proteins as a putative binding site; 3) the N-terminus rather than the C-terminus occupies the site closing off the conventional OBP pocket. The results from fluorescent binding assays, molecular docking and dynamics demonstrate that OBP3 from M. viciae can bind to all four alarm pheromone components and the differential ligand binding between these very similar OBP3s from the two aphid species is determined mainly by the direct π-π interactions between ligands and the aromatic residues of OBP3s in the binding pocket.
Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.|Research Department of Structural and Molecular Biology, University College London, Gower St., London WC1E 6BT, UK.
Tom
T
Northey
Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK.|Laboratorio de Química Ecológica, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera, Temuco, Chile.
Herbert
H
Venthur
Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK.|Dipartimento di Scienze, Università della Basilicata, via dell'Ateneo Lucano 10, 85100 Potenza, Italy.
Filomena
F
De Biasio
Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
Francois-Xavier
FX
Chauviac
Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
Ambrose
A
Cole
Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK.
Karlos Antonio Lisboa
KA
Ribeiro
Dipartimento di Scienze, Università della Basilicata, via dell'Ateneo Lucano 10, 85100 Potenza, Italy.
Gerarda
G
Grossi
Dipartimento di Scienze, Università della Basilicata, via dell'Ateneo Lucano 10, 85100 Potenza, Italy.
Patrizia
P
Falabella
Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK.
Linda M
LM
Field
Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
Nicholas H
NH
Keep
Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK.
Jing-Jiang
JJ
Zhou
D000818:Animals; D001042:Aphids; D005470:Fluorometry; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D010675:Pheromones / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D018035:Receptors, Odorant / Q000737:chemistry* / Q000378:metabolism*
D019476:Insect Proteins; D010675:Pheromones; D018035:Receptors, Odorant; C045648:odorant-binding protein