title: Single Residue Acts as Gate in OccK Channels.
abstract: The OccK protein subfamily located in the outer membrane of Pseudomonas aeruginosa contains dynamic channels with several conformational states that range from open to closed forms. The molecular determinants of the OccK channels that contribute to the diverse gating have, however, remained elusive so far. Performing molecular dynamics (MD) simulations on OccK5 (OpdH) as an example, local fluctuations of loop L7 mediated by a single residue were identified that effectively gate the channel. The features of this gate residue were studied by single-channel electrophysiology and site-directed mutagenesis demonstrating that this gate residue indeed confers unique gating properties to the OccK channels. In support of these functional measurements, MD simulations highlight the correlations between the size of the side-chain belonging to the gate residue on one side and the pore size as well as the L7 flexibility on the other side.
authors.affiliation: Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Karunakar R
authors.initials: KR
authors.lastname: Pothula
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Naresh N
authors.initials: NN
authors.lastname: Dhanasekar
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Usha
authors.initials: U
authors.lastname: Lamichhane
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Farhan
authors.initials: F
authors.lastname: Younas
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Daniel
authors.identifier: 0000-0001-5750-7505
authors.initials: D
authors.lastname: Pletzer
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Benz
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Winterhalter
authors.affiliation: Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany.
authors.forename: Ulrich
authors.identifier: 0000-0002-6114-7431
authors.initials: U
authors.lastname: Kleinekathöfer
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D007473:Ion Channels