Results of PRE by single time point method using spin-labeled SipD in complex with 15N-labeled PrgI. The SipD spin labels are at the following positions: Asn-155, Asp-169 and Lys-173 (A); Ala-285, Ala-296, and Thr-303 (B); Asp-136, Ala-144, and Asp-147 (C); Leu-318 and Lys-324 (D), and Ser-328, Ser-331, and Glu-335 (E). The gray line indicates the (Ipar/Idia) intensity ratio at 1. The positions of the spin labels (spheres) in the coiled-coil (helix α4 or α8) of SipD are color-coded with the PRE plots.