title: Dehydroergosterol as an analogue for cholesterol: why it mimics cholesterol so well-or does it?
abstract: Although dehydroergosterol (DHE) is one of the most commonly used cholesterol (CHOL) reporters, it has remained unclear why it performs well compared with most other CHOL analogues and what its possible limitations are. We present a comprehensive study of the properties of DHE using a combination of time-resolved fluorescence spectroscopy, quantum-mechanical electronic structure computations, and classical atomistic molecular dynamics simulations. We first establish that DHE mimics CHOL behavior, as previous studies have suggested, and then move on to elucidate and discuss the particular properties that render DHE so superior. We found that the main reason why DHE mimics CHOL so well is due to its ability to stand upright in a membrane in a manner that is almost identical to that of CHOL. The minor difference in how DHE and CHOL tilt with respect to membrane normal has only faint effects on structural membrane properties, and even the lateral pressure profiles of model membranes with CHOL or DHE are almost identical. These results suggest that the mechanical/elastic effects of DHE on the function of mechanically sensitive membrane proteins are not substantially different from those of CHOL. Our study highlights similar dynamical behavior of CHOL and DHE, which implies that DHE can mimic CHOL in processes with free energies close to the thermal energy.
authors.affiliation: Department of Physics, Tampere University of Technology , Korkeakoulunkatu 3, 33720 Tampere, Finland.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Pourmousa
authors.forename: Tomasz
authors.initials: T
authors.lastname: Róg
authors.forename: Risto
authors.initials: R
authors.lastname: Mikkeli
authors.forename: Llpo
authors.initials: L
authors.lastname: Vattulainen
authors.forename: Lukasz M
authors.initials: LM
authors.lastname: Solanko
authors.forename: Daniel
authors.initials: D
authors.lastname: Wüstner
authors.forename: Nanna Holmgaard
authors.initials: NH
authors.lastname: List
authors.forename: Jacob
authors.initials: J
authors.lastname: Kongsted
authors.forename: Mikko
authors.initials: M
authors.lastname: Karttunen
mesh_terms: D002784:Cholesterol / Q000031:analogs & derivatives*; D004875:Ergosterol / Q000031:analogs & derivatives* / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D010713:Phosphatidylcholines / Q000737:chemistry; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D053835:Unilamellar Liposomes / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D053835:Unilamellar Liposomes; D014867:Water; C010905:dehydroergosterol; D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; D004875:Ergosterol