FIG. 5.

Superposition of the allosteric site in the T and R states of ScCM. The polypeptide backbones of helices H4-H5 and H8 are displayed in ribbon style. The residues necessary for binding of tyrosine (blue) and tryptophan (red) are shown as sticks with atoms labeled by color (green, carbon; blue, nitrogen; red, oxygen). Apostrophes indicate the position of the residue in an adjacent polypeptide chain. The dimer in the T state is superimposed onto the dimer in the R state by using residues 1 to 214 and 224 to 254.