Crystallization and preliminary structure determination of the plant food allergen Pru av 2

Thaumatin-like proteins (TLPs) have mostly been investigated in the context of their function as pathogenesis-related proteins and only in recent years have some of them been classified as allergens. Here, the purification and crystallization of the first allergenic TLP, Pru av 2, a 23.3 kDa protein isolated from ripe cherries, is reported. The crystals diffracted to 2.1 A resolution at a rotating-anode generator and were found to belong to space group P2(1), with unit-cell parameters a = 44.48, b = 41.04, c = 59.16 A, beta = 106.61 degrees and one molecule per asymmetric unit. In order to obtain high-resolution data, an annealing protocol was applied that improved the resolution limit from 1.6 to 1.3 A at a synchrotron.