Figure 3.

P2-binding site on TCS was mapped to the C-terminal domain by chemical shift perturbation. (a) ¹H–¹⁵N correlation spectra of TCS in the absence (black contours) and in the presence (red contours) of equal molar ratio of P2 were compared, and (b) changes in chemical shifts, ▵ppm(HN) and ▵ppm(N), of amide resonances of TCS were measured. Residues with ▵ppm(HN) >0.075 ppm or ▵ppm(N) >0.5 ppm are indicated in (a) and (b), and colour-coded magenta in the stereo diagram of TCS in (c). These residues are localized in or near the C-terminal domain (173–247, colour-coded green) of TCS. Scanning alanine mutagenesis was performed on all charge residues in the C-terminal domain and E123, which are indicated in (c).