Figure 7.

Contact matrices (heat maps) showing specific interactions between two mutated A_2A TM5 helices (“helix 1” and “helix 2”) with the following residues mutated: M177A (a), M193^5.54A (b), and M193^5.54I (c). Results shown are the average for each ensemble. Interhelical distances at the 15 and 12 Å cutoff distances are shown in the top left and lower right quarter of panels (a–c), respectively. The color scale is as indicated in Figure 6. Circles indicate areas with key interhelical contacts. The identified amino acid interactions are numbered as follows: (1) M193^5.54 with M193^5.54; (2, 3) V196^5.57 with Y197^5.58 and Y197^5.58 with Y197^5.58; (4) Y197^5.58 with I200^5.61 and R199^5.60 with R199^5.60; (5) L192^5.53 with I193^5.54, V196^5.57 with Y197^5.58, and Y197^5.58 with R199^5.60, (6) Y197^5.58 with I200^5.61 and Y197^5.58 with R199^5.60; and (7) R199^5.60 with R199^5.60.