FIGURE 1.

The Q-axis intersubunit regions around Arg¹⁷¹ of LpLDH (A) and TtMDH (B) and the R (C) and T (D) states of TcLDH. The structures are represented by ribbon diagrams, where only the amino acids at positions 67, 68, 171, 178, and 235 are indicated by a stick model. The residues are numbered according to the N system proposed by Eventoff et al. (50). The two Q-axis-related subunits are colored red and blue, as in Fig. 3A. Salt bridges and hydrogen bonds among these amino acids are indicated by green broken lines.