Issue 21, 2021

Potassium and sodium ion complexes with a partial peptide of the selectivity filter in K+ channels studied by cold ion trap infrared spectroscopy: the effect of hydration

Abstract

Potassium channels allow K+ to rapidly diffuse, while the selectivity filter (SF) actively blocks Na+. The presence of water in the SF during ion translocation remains under debate due to the experimental and computational challenges in characterizing the interactions between water, ions, and the SF. Our bottom-up approach has been applied to a system composed of a partial peptide of the SF (Ac-tyrosine-NHMe) with a metal ion and a single water molecule to probe these interactions. The IR photodissociation spectra of M+Ac-tyrosine-NHMe(H2O) (M = Na, K) combined with quantum chemical calculations revealed that the water molecule binding sites are ion-dependent. In addition, the ion–peptide distances are elongated significantly for the K+ complex in comparison to the Na+ complex by the addition of a single water molecule. This striking structural difference with the water molecule is discussed in relation to ion selectivity and translocation within the K+ channel.

Graphical abstract: Potassium and sodium ion complexes with a partial peptide of the selectivity filter in K+ channels studied by cold ion trap infrared spectroscopy: the effect of hydration

Supplementary files

Article information

Article type
Paper
Submitted
02 Mar 2021
Accepted
24 Mar 2021
First published
29 Mar 2021

Phys. Chem. Chem. Phys., 2021,23, 12045-12050

Potassium and sodium ion complexes with a partial peptide of the selectivity filter in K+ channels studied by cold ion trap infrared spectroscopy: the effect of hydration

T. Negoro, K. Hirata, J. M. Lisy, S. Ishiuchi and M. Fujii, Phys. Chem. Chem. Phys., 2021, 23, 12045 DOI: 10.1039/D1CP00936B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements