This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.105.072959v1 90/9/3176    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stottrup, B. L. Articles by Keller, S. L. Search for Related Content PubMed PubMed Citation Articles by Stottrup, B. L. Articles by Keller, S. L.

Phase Behavior of Lipid Monolayers Containing DPPC and Cholesterol Analogs

Departments of Physics and Chemistry, University of Washington, Seattle, Washington 98195

Correspondence: Address reprint requests to Sarah L. Keller, E-mail: slkeller{at}chem.washington.edu.

We investigate the miscibility phase behavior of lipid monolayers containing a wide variety of sterols. Six of the sterols satisfy a definition from an earlier study of "membrane-active sterols" in bilayers (cholesterol, epicholesterol, lathosterol, dihydrocholesterol, ergosterol, and desmosterol), and six do not (25-hydroxycholesterol, lanosterol, androstenolone, coprostanol, cholestane, and cholestenone). We find that monolayers containing dipalmitoyl phosphatidylcholine mixed with membrane-active sterols generally produce phase diagrams containing two distinct regions of immiscible liquid phases, whereas those with membrane-inactive sterols generally do not. This observation establishes a correlation between lipid monolayers and bilayers. It also demonstrates that the ability to form two regions of immiscibility in monolayers is not one of the biophysical attributes that explains cholesterol's predominance in animal cell membranes. Furthermore, we find unusual phase behavior for dipalmitoyl phosphatidylcholine monolayers containing 25-hydroxycholesterol, which produce both an upper and a lower miscibility transition. The lower transition correlates with a sharp change of slope in the pressure-area isotherm.

This article has been cited by other articles:

				K. Sabatini, J.-P. Mattila, and P. K. J. Kinnunen Interfacial Behavior of Cholesterol, Ergosterol, and Lanosterol in Mixtures with DPPC and DMPC Biophys. J., September 1, 2008; 95(5): 2340 - 2355. [Abstract] [Full Text] [PDF]

				M. Vranceanu, K. Winkler, H. Nirschl, and G. Leneweit Surface Rheology and Phase Transitions of Monolayers of Phospholipid/Cholesterol Mixtures Biophys. J., May 15, 2008; 94(10): 3924 - 3934. [Abstract] [Full Text] [PDF]