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.
Department of Biology and Agricultural Plants, University of Pisa, Via S. Michele, 4, 56124, Pisa, Italy.
Huili
H
Qiao
Xiaoli
X
He
Danuta
D
Schymura
Liping
L
Ban
Linda
L
Field
Francesca Romana
FR
Dani
Elena
E
Michelucci
Beniamino
B
Caputo
Alessandra
A
della Torre
Kostas
K
Iatrou
Jing-Jiang
JJ
Zhou
Jürgen
J
Krieger
Paolo
P
Pelosi
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