Normal modes of the NOMPC channel. (A) Side view of the lowest-order NMA performed on the entire NOMPC channel. The starting structure is represented as a white tube, and the cyan and black tube representations of a single AR chain depict the maximum displacement of the chains along mode 1. The trajectory is superposed on the TM domain. The inset shows the cytoplasmic view of the channel highlighting the extreme displacements of the TRP domain (cyan and black) for this mode. As can be seen, the TRP domain moves as a rigid body. The TM domain is at the top, and the MT binding domain is at the bottom. (B) Side view of the lowest-order NMA performed on the entire NOMPC channel with the N-terminal residues clamped. This mode mimics NOMPC binding to an MT. The lowest-order mode still shows the largest deflections along the z axis, but the amplitude is suppressed compared with A. The color scheme is as in A.