Revisiting the specificity of Mamestra brassicae and Antheraea polyphemus pheromone-binding proteins with a fluorescence binding assay.
Pheromone-binding proteins (PBPs), located in the sensillum lymph of pheromone-responsive antennal hairs, are thought to transport the hydrophobic pheromones to the chemosensory membranes of olfactory neurons. It is currently unclear what role PBPs may play in the recognition and discrimination of species-specific pheromones. We have investigated the binding properties and specificity of PBPs from Mamestra brassicae (MbraPBP1), Antheraea polyphemus (ApolPBP1), Bombyx mori (BmorPBP), and a hexa-mutant of MbraPBP1 (Mbra1-M6), mutated at residues of the internal cavity to mimic that of BmorPBP, using the fluorescence probe 1-aminoanthracene (AMA). AMA binds to MbraPBP1 and ApolPBP1, however, no binding was observed with either BmorPBP or Mbra1-M6. The latter result indicates that relatively limited modifications to the PBP cavity actually interfere with AMA binding, suggesting that AMA binds in the internal cavity. Several pheromones are able to displace AMA from the MbraPBP1- and ApolPBP1-binding sites, without, however, any evidence of specificity for their physiologically relevant pheromones. Moreover, some fatty acids are also able to compete with AMA binding. These findings bring into doubt the currently held belief that all PBPs are specifically tuned to distinct pheromonal compounds.
Campanacci
V
V
Architecture et Fonction des Macromolécules Biologiques (AFMB), UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 31 ch. Joseph Aiguier, 13402 Marseille, Cedex 20, France.
Krieger
J
J
Bette
S
S
Sturgis
J N
JN
Lartigue
A
A
Cambillau
C
C
Breer
H
H
Tegoni
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D017931:DNA Primers; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D007915:Lepidoptera; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence
D002352:Carrier Proteins; D017931:DNA Primers; D019476:Insect Proteins; D036341:Intercellular Signaling Peptides and Proteins; D011994:Recombinant Proteins; C403094:pheromone-binding protein, Bombyx; C067715:APR-1 pheromone-binding protein, Antheraea pernyi