Figure 6.

Interactions between DHp and CA domains. Stereoview of the structural elements involved in interdomain contacts and sulfate ion interactions. The DHp domain, CA domain and interdomain-connecting loop are represented in blue, gold and green ribbon diagrams, respectively. Additionally, the α1′ helix, which presents His260′ as a sulfate ligand, is shown in gray. The interacting side chains are shown as sticks with the same carbon atom color as the corresponding domain, except the sulfate-interacting residues that are in gray. Nitrogen, oxygen, sulfur and nucleotide molecule are drawn in blue, red, black and magenta, respectively. Residue labels take the colors of their domains. Hydrogen bonds and salt bridges between the sulfate ion and interacting residues are indicated by purple dots.