Crystallization and preliminary X-ray crystallographic analysis of the plant defensin NaD1

Plant defensins are small (similar to 5 kDa) basic cysteine-rich proteins that are being explored in important agricultural crops for their ability to confer enhanced disease resistance against fungal pathogens. NaD1, isolated from the flowers of the ornamental tobacco (Nicotiana alata), is a particularly well characterized antifungal defensin. Here, the crystallization and preliminary X-ray crystallographic analysis of NaD1 is reported. Crystals of NaD1 were crystallized using the sitting-drop vapour-diffusion method at 291 K. Data were collected from two crystal forms to 1.4 and 1.6 angstrom resolution, respectively. The crystals of form A belonged to the monoclinic space group P21, with unit-cell parameters a = 32.697, b = 32.685, c = 41.977 angstrom, a = 90, beta = 100.828, gamma = 90 degrees, whereas crystals of form B belonged to the trigonal space group P3221, with unit-cell parameters a = b = 33.091, c = 128.77 angstrom, a = beta = 90, gamma = 120 degrees.