11-fold symmetry of the trp RNA-binding attenuation protein (TRAP) from bacillus subtilis determined by X-ray analysis

The trp, RNA-binding attenuation protein (TRAP) of Bacillus sbbtilis has been crystallized and examined by crystallography using X-ray synchrotron radiation diffraction data. Crystals of TRAP complexed with L-tryptophan belong to sp ace group C2 with a 156.8 Å, b = 114.05 Å, c = 105.9 Å, β = 118.2 ^° . Crystals of a potential heavy-atom derivative of TRAP complexed with 5-bromo-L-tryptophan grow in the same space group with similar cell dimensions. X ray data for the native crystals and for the derivative have been collected to 2.9 Å and 2.2 Å resolution, respectively. Peaks in the self-rotation function and in the Patterson synthesis could only be explained by two 11-subunit oligomers (each formed by an 11-fold axis of symmetry) in the asymmetric unit lying with the 11-fold rotation axes parallel to each other. The consequence is that the TRAP molecule has 11-fold symmetry and contains 11 subunits.