Crystallization and preliminary X-ray analysis of brazzein, a new sweet protein.

Brazzein is a sweet protein isolated from a wild African plant Pentadiplandra brazzeana. Brazzein is the smallest (molecular mass = 6473 Da) and the most water-soluble protein sweetener discovered so far and is highly thermostable. Crystals were grown by vapor diffusion using sodium sulfate as a precipitant. They belong to the tetragonal space group I4(1)22 with unit-cell parameters a = b = 61.4, c = 59.6 A and with one molecule in the asymmetric unit. The crystals diffract to 1.8 A resolution using synchrotron radiation.