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Updated: Jun 28, 2026

Gramicidin-based Fluorescence Assay; for Determining Small Molecules Potential for Modifying Lipid Bilayer Properties
Published on: October 13, 2010
Photoelectron spectroscopy of gramicidin polyanions: competition between delayed and direct emission
Katerina Matheis1, Laure Joly, Rodolphe Antoine
1Institut für Physikalische Chemie, Universität Karlsruhe, Kaiserstrasse 12, D-76128 Karlsruhe, Germany.
Abstract:
We present the first photoelectron (PE) spectra of polypeptide polyanions. Combining PE spectroscopy and mass spectrometry provides a direct measurement of the stability of the polyanions with respect to electron detachment and of the repulsive energy between excess charges. The second electron affinity of gramicidin was found to amount to 2.35 +/- 0.15 eV, and the value of the repulsive Coulomb barrier was estimated to be 0.5 +/- 0.15 eV. The spectra are interpreted as resulting from a competition between delayed and direct emission.
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