Chloride Ion Transport by the E. coli CLC Cl^-/H⁺ Antiporter: A Combined Quantum-Mechanical and Molecular-Mechanical Study.

ABSTRACT: We performed steered molecular dynamics (SMD) and umbrella sampling simulations of Cl^- ion migration through the transmembrane domain of a prototypical E. coli CLC Cl^-/H⁺ antiporter by employing combined quantum-mechanical (QM) and molecular-mechanical (MM) calculations. The SMD simulations revealed interesting conformational changes of the protein. While no large-amplitude motions of the protein were observed during pore opening, the side chain rotation of the protonated external gating residue Glu148 was found to be critical for full access of the channel entrance by Cl^-. Moving the anion into the external binding site (S_ext) induced small-amplitude shifting of the protein backbone at the N-terminal end of helix F. As Cl^-

SUBMITTER: Wang CH 

PROVIDER: S-EPMC5859129 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature