title: Intrinsic aqueduct orifices facilitate K+ channel gating.
abstract: The ion-conducting pore of potassium channels, which can open and close to regulate ion passage, was at long thought to be a one-dimensional pore structure with a water-filled central cavity. Here, we find four orifices in the KcsA potassium channel, which are perpendicular to the pore and stretch out from the cavity. Equilibrium molecular dynamics simulations show that water molecules can flow between the cavity and orifices. Targeted molecular dynamics simulations show that during the opening process, water molecules can move into the cavity through the orifices to facilitate channel gating, whereas blocking the aqueduct orifices makes the channel difficult to open.
authors.affiliation: Institute of Nano Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Zhong
authors.forename: Wanlin
authors.initials: W
authors.lastname: Guo
authors.forename: Shaojie
authors.initials: S
authors.lastname: Ma
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D015640:Ion Channel Gating; D008958:Models, Molecular; D016062:Porosity; D015221:Potassium Channels / Q000737:chemistry*; D011487:Protein Conformation; D014867:Water / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D015221:Potassium Channels; C107790:prokaryotic potassium channel; D014867:Water