Figure 1.

The DNA-binding activity of class I TCP proteins is modulated by redox agents. A, Sequence logo constructed with the TCP domain sequences of 218 class I TCP proteins from different species. Position 20 is indicated with the arrow. B, TCP15 (50 ng) purified with buffer lacking 2-ME was incubated in the presence of 25 mm DTT, 10 mm diamide, 25 mm GSH, or 25 mm GSSG, as indicated. The control (–) was incubated under similar conditions without redox agents. After incubation, the DNA-binding activity of TCP15 was analyzed by EMSA. C, A similar experiment as in B using TCP21, TCP20, and TCP15 that had been previously dialyzed in the absence of redox agents as described in “Materials and Methods.” In B and C, the amount of bound DNA, relative to the sample incubated with DTT, is shown below the EMSA images. Experiments were repeated at least three times with similar results.