Fluorescence of nitrobenzoxadiazole (NBD) labeled lipids in model membranes is connected not to lipid mobility, but to probe location

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F16%3A00453494" target="_blank" >RIV/61388955:_____/16:00453494 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1039/c5cp05238f" target="_blank" >http://dx.doi.org/10.1039/c5cp05238f</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c5cp05238f" target="_blank" >10.1039/c5cp05238f</a>

Result language

angličtina

Original language name

Fluorescence of nitrobenzoxadiazole (NBD) labeled lipids in model membranes is connected not to lipid mobility, but to probe location

Original language description

Nitrobenzoxadiazole (NBD)-labeled lipids are popular fluorescent membrane probes. However, understanding of important aspects of NBD photophysics remains incomplete, including the observed shift in the emission spectrum of NBD-lipids to longer wavelengths following excitation at the red-edge of the absorption spectrum (red-edge excitation shift or REES). REES of NBD-lipids has been previously interpreted as reflecting restricted mobility of solvent surrounding the fluorophore in membrane environments. However, this requires a large change in dipole moment (Δμ) of NBD upon excitation. Previous calculations of Δμ of NBD in the literature have been carried out using outdated semiempirical methods, leading to conflicting values. Using up-to-date density functional theory methods, we recalculated Δμ confirming a rather small value (2 D). Fluorescence measurements confirmed a REES of 16 nm for 1,2-dioleoyl-sn-glycero-3-phospho-L-serine-N-(NBD) (NBD-PS) in dioleoylphosphatidylcholine vesicles. However, the observed shift is independent on both temperature and presence of cholesterol, and is therefore insensitive to membrane mobility and hydration. Moreover, red-edge excitation leads to an increased contribution of the shorter lifetime decay component, while time-resolved emission spectra of NBD-PS showed an atypical blue-shift following excitation. This excludes solvent relaxation restrictions as cause for the measured NBD REES and TRES pointing instead to heterogeneous probe transverse location as the origin of these effects. The latter hypothesis was confirmed by molecular dynamics simulations, from which calculated NBD hydration/location heterogeneity correlated with measured fluorescence lifetimes/REES. Altogether, our combination of theory and experiment-based techniques has led to a considerably improved understanding of NBD photophysics and a reinterpretation of its REES in particular.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

CF - Physical chemistry and theoretical chemistry

OECD FORD branch

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Project

<a href="/en/project/GBP208%2F12%2FG016" target="_blank" >GBP208/12/G016: Controlling structure and function of biomolecules at the molecular scale: theory meets experiment</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

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Volume of the periodical

18

Issue of the periodical within the volume

10

Country of publishing house

GB - UNITED KINGDOM

Number of pages

13

Pages from-to

7042-7054

UT code for WoS article

000371608600011

EID of the result in the Scopus database

2-s2.0-84960153667