Figure 2. The inactive tDGC dimer (a) The two monomers present in the asymmetric unit are colored in grey and yellow respectively with the two bridging c-di-GMP molecules shown as sticks.

The views are along (left) and perpendicular (right) to the non-crystallographic dyad. (b) Stereoview of the dimerization mediated by two c-di-GMP molecules (labeled c-di-GMP1 and c-di-GMP2), bound at the I-site of tDGC, forcing the GGDEF domain in an inhibited conformation, with both A-sites facing away from each other. An omit map (blue mesh) with Fourier coefficients 2F_o-F_c, where the c-di-GMP ligand was omitted from phase calculation is shown at 1σ contour level. Residues from the RxxD motif at the I-site forming hydrogen bonds with the bound c-di-GMP molecules are displayed as sticks and the distances between interacting atoms are displayed. The same color code as in panel a is used.