Sterol binding assay using surface plasmon fluorescence spectroscopy

Birgit Wiltschi*, Michael Schober, Sepp D. Kohlwein, Dieter Oesterhelt, Eva Kathrin Sinner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We describe the design of a novel in vitro assay to study the interaction of soluble protei ns with small hydrophobic sterol ligands. The sterol molecules are incorporated in an artificial membrane system in order to mimic their arrangement found in a biomembrane. The artificial membrane setup is monitored in real time by surface plasmon spectroscopy. Binding of fluorescently labeled soluble protein is observed by optical detection with surface plasmon enhanced fluorescence spectroscopy. By application of the novel assay, we demonstrate that four different oxidized sterol molecules are specifically recognized by the yeast protein Osh5p, a presumed oxysterol binding protein. Osh5p from yeast is the first oxysterol binding protein homologue for which oxysterol binding is shown with this new technique. With the design of our novel in vitro oxysterol binding assay, we have solved the technically challenging difficulty of presenting hydrophobic ligands to hydrophilic proteins in aqueous media.

Original languageEnglish
Pages (from-to)547-555
Number of pages9
JournalAnalytical Chemistry
Issue number2
Publication statusPublished - 15 Jan 2006

ASJC Scopus subject areas

  • Analytical Chemistry


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