Figure 6.

Analysis of secondary chemical shifts indicates that AP180 M5 contains no regions of α helical or β street structure, in either the free or bound state. It has been reported that for residues in stable α helices, the average secondary chemical shifts are 2.5 ppm for ¹³C^α and −0.38 ppm for ¹H^α, with near random coil values for ¹³C^β and positive values for ¹³C^o. In stable β sheets, the average secondary chemical shifts are −2.0 ppm for ¹³C^α, 2.5 ppm for ¹³C^β and 0.38 ppm for ¹H^α, with negative values for ¹³C^o75. A. Secondary chemical shifts of free 500 μM ¹⁵N-¹³C labeled AP180 M5 for ¹³C^α, ¹³C^β, ¹³C^o and ¹H^α were calculated by subtracting random coil shifts corrected for sequence-dependent variations from the experimental chemical shifts. No regions with patterns indicative of either α helix or β sheet were identified. B. Secondary chemical shifts of 500 μM ¹⁵N-¹³C labeled AP180 M5 with 500 μM unlabeled clathrin TD for ¹³C^o and ¹H^α were calculated in the same way. No regions with patterns indicative of either α helix or β sheet were identified.