The crystal structure of the trp RNA-binding attenuation protein of Bacillus subtilis solved at 1.8 Å resolution reveals a novel structural arrangement in which the eleven subunits are stabilized through eleven intersubunit β-sheets to form a β-wheel with a large central hole. The nature of the binding of L-tryptophan in clefts between adjacent β-sheets in the β-wheel suggests that this binding induces conformational changes in the flexible residues 25-33 and 49-52. It is argued that upon binding, the messenger RNA target forms a matching circle in which eleven U/GAG repeats are bound to the surface of the protein ondecamer modified by the binding of L-tryptophan.
- Alfred A. Antson
- John Otridge
- Paul Gollnick
