Cooperative interactions between odorant-binding proteins of Anopheles gambiae.
To understand olfactory discrimination in Anopheles gambiae, we made six purified recombinant OBPs and investigated their ligand-binding properties. All OBPs were expressed in bacteria with additional production of OBP47 in the yeast Kluveromyces lactis. Ligand-binding experiments, performed with a diverse set of organic compounds, revealed marked differences between the OBPs. Using the fluorescent probe N-phenyl-1-naphthylamine, we also measured the binding curves for binary mixtures of OBPs and obtained, in some cases, unexpected behaviour, which could only be explained by the OBPs forming heterodimers with binding characteristics different from those of the component proteins. This shows that OBPs in mosquitoes can form complexes with novel ligand specificities, thus amplifying the repertoire of OBPs and the number of semiochemicals that can be discriminated. Confirmation of the likely role of heterodimers was demonstrated by in situ hybridisation, suggesting that OBP1 and OBP4 are co-expressed in some antennal sensilla of A. gambiae.
Qiao
Huili
H
Department of Biology and Agricultural Plants, University of Pisa, Via S. Michele, 4, 56124, Pisa, Italy.
He
Xiaoli
X
Schymura
Danuta
D
Ban
Liping
L
Field
Linda
L
Dani
Francesca Romana
FR
Michelucci
Elena
E
Caputo
Beniamino
B
della Torre
Alessandra
A
Iatrou
Kostas
K
Zhou
Jing-Jiang
JJ
Krieger
Jürgen
J
Pelosi
Paolo
P
D015057:1-Naphthylamine / Q000031:analogs & derivatives / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000378:metabolism*; D003001:Cloning, Molecular; D019281:Dimerization; D005456:Fluorescent Dyes / Q000494:pharmacology; D008969:Molecular Sequence Data; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D058618:Sensilla / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D005456:Fluorescent Dyes; D020033:Protein Isoforms; D018035:Receptors, Odorant; D011994:Recombinant Proteins; C045648:odorant-binding protein; C005444:N-phenyl-1-naphthylamine; D015057:1-Naphthylamine