Conformational plasticity in the KcsA potassium channel pore helix revealed by homo-FRET studies

04/17/2019

<jats:title>Abstract</jats:title><jats:p>Potassium channels selectivity filter (SF) conformation is modulated by several factors, including ion-protein and protein-protein interactions. Here, we investigate the SF dynamics of a single Trp mutant of the potassium channel KcsA (W67) using polarized time-resolved fluorescence measurements. For the first time, an analytical framework is reported to analyze the homo-Förster resonance energy transfer (homo-FRET) within a symmetric tetrameric protein with a square geometry. We found that in the closed state (pH 7), the W67-W67 intersubunit distances become shorter as the average ion occupancy of the SF increases according to cation type and concentration. The hypothesis that the inactivated SF at pH 4 is structurally similar to its collapsed state, detected at low K<jats:sup>+</jats:sup>, pH 7, was ruled out, emphasizing the critical role played by the S2 binding site in the inactivation process of KcsA. This homo-FRET approach provides complementary information to X-ray crystallography in which the protein conformational dynamics is usually compromised.</jats:p>

Authors in the community:

• 

  A

  Alexander Andreevich Fedorov

  ist90123

  Affiliations and sources

  IST > CQFM

  Centro de Química-Física Molecular

  In: cienciavitae

  ID: 1427389

VoR - Version of Record

Springer Science and Business Media LLC

Scientific Reports

9

1

2045-2322

10.1038/s41598-019-42405-5

biological-sciences - Biological sciences

Keywords

• Multidisciplinary

eng - English

http://dx.doi.org/10.1038/s41598-019-42405-5