Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy

Albert Cha, Gregory E. Snyder, Paul R Selvin, Francisco Bezanilla

Research output: Contribution to journalArticlepeer-review

Abstract

Voltage-gated ion channels are transmembrane proteins that are essential for nerve impulses and regulate ion flow across cell membranes in response to changes in membrane potential. They are made up of four homologous domains or subunits, each of which contains six transmembrane segments. Studies of potassium channels have shown that the second (S2) and fourth (S4) segments contain several charged residues, which sense changes in voltage and from part of the voltage sensor. Although these regions dearly undergo conformational changes in response to voltage, little is known about the nature of these changes because voltage-dependent distance changes have not been measured. Here we use lanthanide-based resonance energy transfer to measure distances between Shaker potassium channel subunits at specific residues. Voltage-dependent distance changes of up to 3.2 Å were measured at several sites near the S4 segment. These movements directly correlated with electrical measurements of the voltage sensor, establishing the link between physical changes and electrical charge movement. Measured distance changes suggest that the region associated with the S4 segment undergoes a rotation and possible tilt, rather than a large transmembrane movement, in response to voltage. These results demonstrate the first in situ measurement of atomic scale movement in a transmembrane protein.

Original languageEnglish (US)
Pages (from-to)809-813
Number of pages5
JournalNature
Volume402
Issue number6763
DOIs
StatePublished - Dec 16 1999

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy'. Together they form a unique fingerprint.

Cite this