Coil-to-helix transition and ligand release of Bombyx mori pheromone-binding protein.
Lautenschlager, C., Leal, W.S., Clardy, J.(2005) Biochem Biophys Res Commun 335: 1044-1050
- PubMed: 16111659 
- DOI: https://doi.org/10.1016/j.bbrc.2005.07.176
- Primary Citation of Related Structures:  
2FJY - PubMed Abstract: 
The transport of hydrophobic insect pheromones through the aqueous medium surrounding their receptors is assisted by pheromone-binding proteins (PBPs). The protein from the silkworm moth Bombyx mori, BmorPBP, exhibits a pH-dependent conformational change postulated to trigger the release of the pheromone bombykol to its receptor. At low pH, an alpha-helix occupies the same binding pocket that houses the pheromone in the BmorPBP-bombykol complex at high pH. We have determined the crystal structure of apo BmorPBP at a resolution of 2.3 angstroms and pH 7.5, which has surprisingly a structure similar to the A-form. These data suggest that BmorPBP undergoes a ligand-dependent conformational change in addition to the previously described pH-dependent conformational change. Analysis of the alpha-helix occupying the binding pocket reveals an amphipathic helix with three acidic residues along one face that are conserved among lepidopteran PBPs and may be involved in a conformational transition of BmorPBP at the receptor membrane.
Organizational Affiliation: 
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.