EXPRESSION OF A LIPOCALIN IN PICHIA-PASTORIS - SECRETION, PURIFICATION AND BINDING-ACTIVITY OF A RECOMBINANT MOUSE MAJOR URINARY PROTEIN

The proteins of the mouse major urinary protein complex (MUP), members of the lipocalin family, bind volatile pheromones and interact with t he vomeronasal neuroepithelium of the olfactory system, We report the expression of a MUP protein using its native signal sequence for secre tion in the methylotrophic yeast, Pichia pastoris. Mature recombinant MUP (rMUP) is secreted at a concentration of 270 mg/l in minimal mediu m and it is isolated from the culture supernatant by one step ion-exch ange chromatography in a nearly pure form, Binding activity, tested wi th an odorant molecule which displays high affinity for native MUP, in dicates that rMUP has a behavior similar to the native one, This findi ng suggests that the protein, and in particular its hydrophobic bindin g pocket, is properly folded.