Assembly of the Transmembrane Domain of E. coli PhoQ Histidine Kinase: Implications for Signal Transduction from Molecular Simulations
Figure 5
Solvation-dependent dynamic features of the TM domain.
(A) The rotation of the Cα atoms around the TM2 helix main axis is computed based on a principal component analysis, and the angle distribution is characterized by three major modes, that can be fitted using three Gaussians, (B) MD time series of the TM2 residue state corresponding to the angle distribution. The system is initially in a metastable state (black), before switching to a solvated state where the TM1-TM1 interface is tighter (grey). After ∼30 ns, the system, passing through to a metastable state, shifts to a stable state characterized by a larger TM1-TM1 distance (light grey). (C) The rotation per residue related to the switch between the 2 most relevant states in MD (B) is calculated. TM2 Pro208 acts like a hinge, and transforms the large movement of the N-terminus into a mild rotation (∼20 degrees) of the TM2 residue at the cytoplasmic interface.