Crystallization and preliminary crystallographic study of a pheromone-binding protein from the cockroach Leucophaea maderae

Pheromone-binding proteins (PBPs) are small helical proteins (13–­18 kDa) present in various sensory organs of moths and other insect species. An antennal protein from the cockroach Leucophaea maderae (LmaPBP) has been found to share all the hallmarks of the PBP family and is expressed specifically in the female adult antennae, the gender that perceives the sex pheromone. Here, the crystallization of LmaPBP expressed as a recombinant protein in Escherichia coli periplasm is reported. Crystals of LmaPBP were obtained by the sitting-drop vapour-diffusion method using a nanodrop-dispensing robot. The protein crystallizes in two different crystal forms. Form 1 belongs to space group P1, with unit-cell parameters a = 43.2, b = 45.1, c = 45.7 Å, α = 118.6, β = 93.0, γ = 106.9°. With two molecules in the asymmetric unit, V_M is 2.7 ų Da⁻¹ and the solvent content is 47%. A complete data set has been collected at 1.6 Å resolution on beamline ID14-2 (ESRF, Grenoble). Form 2 was obtained in the presence of the pheromone (3-hydroxy-butan-2-one) and belongs to space group P2₁, with unit-cell parameters a = 38.2, b = 62.2, c = 45.1 Å, β = 93.0°. With two molecules in the asymmetric unit, V_M is 2.0 ų Da⁻¹ and the solvent content is 39%. A complete data set has been collected at 1.7 Å resolution on beamline BM14 (ESRF, Grenoble). SeMet expression has been performed with a view to solving the structure by MAD data collection using the Se absorption edge.