title: A single amino acid gates the KcsA channel.
abstract: The KcsA channel is a proton-activated potassium channel. We have previously shown that the cytoplasmic domain (CPD) acts as a pH-sensor, and the charged states of certain negatively charged amino acids in the CPD play an important role in regulating the pH-dependent gating. Here, we demonstrate the KcsA channel is constitutively open independent of pH upon mutating E146 to a neutrally charged amino acid. In addition, we found that rearrangement of the CPD following this mutation was not large. Our results indicate that minimal rearrangement of the CPD, particularly around E146, is sufficient for opening of the KcsA channel.
authors.affiliation: Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku Hamamatsu, Shizuoka 431-1202, Japan; Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan. Electronic address: hirano37@gpi.ac.jp.
authors.forename: Minako
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan. Electronic address: dokuno@riken.jp.
authors.forename: Daichi
authors.initials: D
authors.lastname: Okuno
authors.affiliation: Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan. Electronic address: yonishi@riken.jp.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Onishi
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Kita-ku Okayama-shi, Okayama 700-8530, Japan. Electronic address: ide@okayama-u.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Ide
mesh_terms: D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating; D008856:Microscopy, Fluorescence; D016297:Mutagenesis, Site-Directed; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*
chemical_list: D015221:Potassium Channels
keywords: Ion channel; KcsA channel; Rearrangement; Single-channel recording; pH-dependent gating