The antenna of the male B. mori silkworm moth is exquisitely sensitive to the female sex pheromone bombykol; as little as 3,000 molecules of bombykol per mL of air can evoke a behavioral response. This sensitivity requires the use of the pheromone binding protein (PBP) to carry the highly hydrophobic pheromone through the aqueous environment of the sensillary lymph to odorant receptors on the olfactory neuron.
Function
The B. mori PBP contains an interior, hydrophobic pocket into which the pheromone ligand binds. A conserved residue,
forms hydrogen bonds with the hydroxyl functional group of the pheromone; this is mutated to alanine in lepidopteran species which use acetyl esters as pheromones. Some species with multiple pheromone components possess multiple PBP isoforms, suggesting a role in odorant discrimination as well.
Structural highlights
This is a sample scene created with SAT to by Group, and another to make of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.
