Purification, crystallization and preliminary X-ray diffraction analysis of a novel mannose-binding lectin from Gastrodia elata with antifungal properties.

A plant antifungal protein, Gastrodia antifungal protein (GAFP-1) has been isolated from terminal corms of the orchid Gastrodia elata B1 f. elata, purified to homogeneity and crystallized by means of the hanging-drop vapour-diffusion method. The best quality crystals grew over several months at 277 K. The crystal used for data collection belongs to the space group P2(1)2(1)2, with unit-cell parameters a = 61.087, b = 91.488, c = 81.132 A. Using a synchrotron-radiation source, the resolution limit of the data reached 2.0 A, with an overall R(merge) of 0.097 and a completeness of 99.8%. Four independent molecules were estimated to be present in the asymmetric unit, with a solvent content of 46.3%. This data will help to solve the first structure of a monomeric monocot mannose-binding lectin.