SECONDARY STRUCTURE AND TERTIARY FOLD OF THE BIRCH POLLEN ALLERGEN BET-V-1 IN SOLUTION

Bet v 1 is the major birch pollen allergen and therefore the main caus e of type I allergies observed in early spring. It is composed of 159 amino acid residues adding up to a molecular mass of 17 kDa. We determ ined the secondary structure and tertiary fold of full-length Bet v 1 by NMR spectroscopy. Two- and three-dimensional NMR measurements sugge st that Bet v 1 is a globular monomer in solution with a high content of well defined secondary structure. Of the total of 159 residues, 135 could be sequentially assigned, using an improved assignment strategy based mainly on heteronuclear experiments. An improved strategy for s tructure calculation revealed three helices and two beta-sheets as maj or elements of secondary structure. The globular tertiary structure is mainly stabilized by two antiparallel beta-sheets, The two helices at the C terminus are in accordance with the results from the solution s tructure of the chemically synthesized peptide Bet v 1-(125-154). This peptide is composed of two helices connected by a hinge. The structur al features of Bet v 1 are highly similar to those found in the Ambros ia allergen Amb t V.