Purification and crystallization of Japanese pear S-RNase associated with gametophytic self-incompatibility.

S-RNase is a 25 kDa pistil-specific protein associated with gametophytic self-incompatibility. The S-RNase is secreted into the transmitting tissue of the pistil and is responsible for the discrimination of pollen S-alleles. Crystals of Japanese pear S(3)-RNase were obtained by the hanging-drop vapour-diffusion method. Preliminary X-ray data showed that the crystals diffract to a 1.5 A resolution and belong to the space group P2(1), with unit-cell parameters a = 45.4, b = 52.4, c = 47.4 A, alpha = gamma = 90, beta = 106.5 degrees.