NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Hydration of Conduction Pores in KcsA Potassium Channel and M2 Proton Channel
Published
Author(s)
J L. Blasic, David L. Worcester, Klaus Gawrisch, Philip A. Gurnev, Mihaela Mihailescu
Abstract
Water-filled hydrophobic cavities of channel proteins serve as gateways for transfer of ions across membrane. However, functional implications of hydration-dehydration transitions remain elusive due to difficulties to detect and quantify water in channel cavities. Here we employ neutron diffraction to determine water distributions in two tetrameric channels embedded in lipid bilayers: potassium channel KcsA and trans-membrane domain of M2 protein of Influenza A virus. We show that for the KcsA channel in the closed state, the distribution of water is peaked in the middle of the membrane, showing water in the central cavity. This water is displaced by the channel blocker tetrabutyl-ammonium. We quantify amounts of water associated with the channel, using neutron diffraction and solid-state NMR. In contrast, the M2 proton channel shows a "V"- shaped water profile across the membrane, with a narrow constriction at the center, like the hour-glass shape of its internal surface.
Blasic, J.
, Duewer, D.
, Gawrisch, K.
, , P.
and Mihailescu, M.
(2015),
Hydration of Conduction Pores in KcsA Potassium Channel and M2 Proton Channel, Journal of Biological Chemistry, [online], https://doi.org/10.1074/jbc.M115.661819
(Accessed October 7, 2025)