A single amino acid gates the KcsA channel

Minako Hirano; Daichi Okuno; Yukiko Onishi; Toru Ide

doi:10.1016/j.bbrc.2014.07.032

A single amino acid gates the KcsA channel

Biochem Biophys Res Commun. 2014 Aug 8;450(4):1537-40. doi: 10.1016/j.bbrc.2014.07.032. Epub 2014 Jul 11.

Authors

Minako Hirano¹, Daichi Okuno², Yukiko Onishi³, Toru Ide⁴

Affiliations

¹ 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.
² Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan. Electronic address: dokuno@riken.jp.
³ Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan. Electronic address: yonishi@riken.jp.
⁴ 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.

PMID: 25019991
DOI: 10.1016/j.bbrc.2014.07.032

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.

Keywords: Ion channel; KcsA channel; Rearrangement; Single-channel recording; pH-dependent gating.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Hydrogen-Ion Concentration
Ion Channel Gating*
Microscopy, Fluorescence
Mutagenesis, Site-Directed
Potassium Channels / genetics
Potassium Channels / physiology*

Substances

Potassium Channels