Figure 4.

Detailed view of interactions between the side chains of Arg²⁵⁸ in switch 3, Glu⁵⁰, and Arg²⁰¹ based on the crystal structure of GTPγS-α_s. The interaction between the side chain of Arg²⁵⁸ and the backbone oxygen of Gln¹⁷⁰ also is shown. Hydrogen bonds are shown as dotted lines. The figure was generated with look 3.0 (Molecular Applications Group, Palo Alto, CA) by using coordinates for the short form of bovine GTPγS-α_s [Protein Data Bank accession code 1AZT (14)], although the numbering in the figure corresponds to the long form of α_s.