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Conformational Changes as Driving Force for Phase Recognition: The Case of Laurdan

Journal Contribution - Journal Article

The development of a universal probe to assess the phase of a lipid membrane is one of the most ambitious goals for fluorescence spectroscopy. The ability of a well-known molecule as Laurdan to reach this aim is here exploited as the behavior of the probe is fully characterized in a dipalmitoyl-phosphatidylcholine (DPPC) solid gel (So) phase by means of molecular dynamics simulations. Laurdan can take two conformations, depending on whether the carbonyl oxygen points toward the beta-position of the naphthalene core (Conf-I) or to the alpha-position (Conf-II). We observe that Conf-I has an elongated form in this environment, whereas Conf-II takes an L-shape. Interestingly, our theoretical calculations show that these two conformations behave in an opposite way from what is reported in the literature for a DPPC membrane in a liquid disordered (Ld) phase, where Conf-I assumes an L-shape and Conf-II is elongated. Moreover, our results show that in DPPC (So) no intermixing between the conformations is present, whereas it has been seen in a fluid environment such as DOPC (Ld). Through a careful analysis of angle distributions and by means of the rotational autocorrelation function, we predict that the two conformers of Laurdan behave differently in different membrane environments.
Journal: Langmuir
ISSN: 0743-7463
Issue: 35
Volume: 35
Pages: 11471 - 11481
Publication year:2019
BOF-keylabel:yes
IOF-keylabel:yes
BOF-publication weight:1
CSS-citation score:1
Authors:International
Authors from:Higher Education
Accessibility:Closed