Figure 4.

Stability of Mutant His₆-TPase_674–777 Derivative Dimers.

His₆-TPase_674–777 (lane WT) and derivatives thereof carrying the amino acid substitution mutations shown in Figure 3 (lanes 1 to 9) were purified by column chromatograph under denaturing conditions, eluted in 8 M urea, and loaded directly onto an SDS-containing 17.5% polyacrylamide gel. The gel was blotted, and the proteins were visualized by immunofluorescence staining. Migration of the size markers (in kilodaltons) is indicated at left. D, dimeric protein; M, monomeric protein.