FIGURE 7.

Dynamics of ¹⁵N-labeled IC:1–143 in a quaternary complex with p150^Glued and light chains. A, overlay of ¹H-¹⁵N HSQC spectra of apo-IC:1–143 (black) and IC:1–143_LL in complex with excess p150_221–509^Glued and LC8 (green); spectra were recorded at pH 6.5 and 20 °C in 10 mm sodium phosphate buffer. Labeled peaks correspond to those whose relative peak volumes remain at 60% or greater intensity for IC:1–143_LL in the quaternary complex. B, T₂ relaxation times collected at 20 °C for apo-IC:1–143 (bars) and the remaining visible peaks of IC:1–143_LL in complex with excess p150^Glued and LC8 (green circles). A dashed line is drawn through the plot to facilitate visual comparison. C, strips from SDS-polyacrylamide gel analysis of components and of the assembled IC quaternary complex used for NMR experiments; IC:1–143_LL (lane 2), p150_221–509^Glued (lane 3), a binary complex of IC:1–143_LL saturated with p150_221–509^Glued (lane 4), LC8 (lane 5), and a quaternary complex of IC:1–143_LL combined with saturating amounts of both p150_221–509^Glued and LC8 (lane 6).