Structure Changes of a Membrane Polypeptide under an Applied Voltage Observed with Surface-Enhanced 2D IR Spectroscopy.

ABSTRACT: The structures of many membrane-bound proteins and polypeptides depend on the membrane potential. However, spectroscopically studying their structures under an applied field is challenging, because a potential is difficult to generate across more than a few bilayers. We study the voltage-dependent structures of the membrane-bound polypeptide, alamethicin, using a spectroelectrochemical cell coated with a rough, gold film to create surface plasmons. The plasmons sufficiently enhance the 2D IR signal to measure a single bilayer. The film is also thick enough to conduct current and thereby apply a potential. The 2D IR spectra resolve features from both 3₁₀- and α-helical structures and cross-peaks connecting the two. We observe changes in the peak intensity, not their frequencies,

SUBMITTER: Birdsall ER 

PROVIDER: S-EPMC8162810 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature