Queen Bee Pheromone Binding Protein pH-Induced Domain Swapping Favors Pheromone Release

Crystal structure of Apis mellifera OBP14, a C-minus odorant-binding protein, and its complexes with odorant molecules

“…Furthermore, the crystals were generated at pH 6 or pH 10 and lead to the same structure. This rules out the mechanism of ligand release observed in lepidopteran PBPs, which is definitively restricted to the "long classical OBPs" (see the discussion in Pesenti et al, 2008Pesenti et al, , 2009). Most probably, there are many different ligand entry and release mechanisms for different OBPs.…”

“…The carboxylic group of the last residue is tightly bound by two strong hydrogen bonds to two residues belonging to the protein core. In Amel ASP1, a mechanism of domain swapping occurs, controlled by ligand binding and pH (Pesenti et al, 2009(Pesenti et al, , 2008. The third and shortest sub-class has C-terminus finishing at the cavity entrance, as described for the PBP of the cockroach Leucophera maderae (Lartigue et al, 2003) or ASP2 OBP from Amel (Lescop et al, 2009).…”

Crystal and Solution Studies of the “Plus-C” Odorant-binding Protein 48 from Anopheles gambiae

“…Three-dimensional domain swapping has been previously observed in the case of a bovine OBP (57) as well as in the honeybee (hymenoptera Apis mellifera) pheromone-binding protein ASP1 (58), but the AgamOBP48 swapped dimer represents the first example for a mosquito (dipteran) OBP. Notably, as in AgamOBP48, bovine OBP dimerization results in the generation of a novel, combined binding site.…”

Review An overview of odorant-binding protein functions in insect peripheral olfactory reception

“…It seems that pH dependence of ligand release has been adapted to local pH around the membrane of the OBP's corresponding neuron cell. The Asp35 residue is demonstrated to be essential for the formation of dimmer, which has 10-fold lower affinity for ligand at neutral pH than monomeric ASP1 at pH 4 (Pesenti et al, 2009).…”

“…For the honey bee, the affinity of another OBP, the antennal-specific protein 1 (ASP1), for 9-keto-2(E)-decenoic acid (9-ODA) is opposite to the pH-dependent affinity of the insects mentioned above (Pesenti et al, 2008(Pesenti et al, , 2009. At low pH (4), ASP1 binds to 9-ODA with higher affinity than at neutral pH.…”