Anti-TRAP protein from Bacillus subtilis: crystallization and internal symmetry.

Anti-TRAP protein regulates the expression of tryptophan biosynthetic genes by binding to TRAP and preventing formation of the TRAP-RNA complex. Anti-TRAP from Bacillus subtilis has been crystallized by vapour diffusion. The crystals belong to space group P1, with unit-cell parameters a = 51.6, b = 60.1, c = 60.4 A, alpha = 114.0, beta = 101.4, gamma = 100.5 degrees. X-ray data have been collected to 2.8 A resolution. Peaks in the self-rotation function correspond to four trimers in the unit cell related by twofold and threefold rotational axes. The symmetry and gel-filtration data suggest that the protein exists as a trimer or a dodecamer in solution.