Dipole moment change of NBD group upon excitation studied using solvatochromic and quantum chemical approaches: Implications in membrane research

Mukherjee, Sushmita; Chattopadhyay, Amitabha; Samanta, Anunay; Soujanya, T.

doi:10.1021/j100062a014

Cited by 121 publications

(124 citation statements)

References 10 publications

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“…At 20 O C the extrapolated to zero surface pressure of solid phase was 0.66 nm 2 which is in excellent agreement with our molecular conformational analysis at simulated air-water interface which predicts a MMA of the solid phase of 0.69 nm 2 [6]. The main absorption band at 460 nm for NBDlabelled lipids is due to intramolecular charge transfer [7], which is accompanied by a large (~ 4 Debye) change in dipole moment [8]. As the experiments here were carried in light this dipole moment is present.…”

Section: Resultssupporting

confidence: 84%

First observation of 3D aggregates in a single-component Langmuir film below the equilibrium spreading pressure

Ivanov

Polevska

2017

MATEC Web Conf.

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Abstract. Single component monolayers from Dipalamitoyl Phosphatidyl Ethanolamine head labelled with the fluorescent chromophore NitroBenzoxaDiazole (DP-NBD-PE) were investigated at the air-water interface as Langmuir films and deposited on silicon wafers or glass plates as Langmuir-Blodgett (LB) films. A step compression and monitoring of the pressure relaxation together with domain formation as observed with Brewster angle microscopy suggests that main transition from liquid expanded to liquid compressed state start at around 6.9 mN/m though on the isotherm it starts around 9 mN/m at 25 o C. Brewster angle microscopy also reveals a nonuniform structure in the monolayer. 3D aggregates -cylinders with 50 -150 nm diameter and bilayer height were observed with Atomic Force Microscopy when deposition was carried at 7 mN/m, above the main phase transition but considerably lower than the equilibrium spreading pressure of 19.6 mN/m for this molecule. When LB film deposition is carried just below the main phase transition a uniform height layer of film in a liquid phase is observed with AFM with no structures. Both compression and deposition were carried at very low speeds with large time to relax in ordered to avoid kinetic effects. These 3D aggregates are not due to the transfer process or interaction with the substrate. These aggregates provide a highly developed area combined with monolayer thick structure which can produce very fast and highly sensitive biosensors.

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Section: Resultssupporting

confidence: 84%

First observation of 3D aggregates in a single-component Langmuir film below the equilibrium spreading pressure

Ivanov

Polevska

2017

MATEC Web Conf.

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“…In general, the dipole moment of molecules increases upon excitation. 30 Although less common, dipole moment has been shown to decrease in the excited state for some probes. Nonetheless, these probes are capable of exhibiting REES (e.g., the dipole moment of a merocyanine dye decreases by ∼5.5 D upon excitation).…”

Section: Rees: Conceptual Frameworkmentioning

confidence: 99%

Organization and Dynamics of Membrane Probes and Proteins Utilizing the Red Edge Excitation Shift

2011

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Dynamics of confined water has interesting implications in the organization and function of molecular assemblies such as membranes. A direct consequence of this type of organization is the restriction imposed on the mobility of the constituent structural units. Interestingly, this restriction (confinement) of mobility couples the motion of solvent (water) molecules with the slow moving molecules in the assembly. It is in this context that the red edge excitation shift (REES) represents a sensitive approach to monitor the environment and dynamics around a fluorophore in such organized assemblies. A shift in the wavelength of maximum fluorescence emission toward higher wavelengths, caused by a shift in the excitation wavelength toward the red edge of the absorption band, is termed REES. REES relies on slow solvent reorientation in the excited state of a fluorophore that can be used to monitor the environment and dynamics around a fluorophore in a host assembly. In this article, we focus on the application of REES to monitor organization and dynamics of membrane probes and proteins.

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“…The fluorescence (excitation wavelength 475 nm, emission wavelength 525 nm) due to the NBD group present in NBDphospholipids has made it possible not only to ascertain the asymmetric nature of most of the phospholipids, but also to study the kinetics of phospholipid translocation (Mukherjee et al, 1994;Williamson et al, 1995;Chattopadhyay and London, 1988). Although NBD-phospholipids have been successfully used to measure out-to-in and in-to-out directed membrane phospholipid translocation in a variety of higher eukaryotic cell membranes or organelles (Diaz and Schroit, 1996;Haest et al, 1997;Angeletti and Nichols, 1998;Bevers et al, 1999), their use in yeast cells has been rather limited (Kean et al, 1997;Siegmund et al, 1998;Marx et al, 1999).…”

Section: Labelling Of Plasma Membrane Of Ad and Its Transformants Witmentioning

confidence: 99%

ABC transporters Cdr1p, Cdr2p and Cdr3p of a human pathogen Candida albicans are general phospholipid translocators

Smriti

Krishnamurthy

Dixit

et al. 2002

Yeast

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We have used fluorescent 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-tagged phospholipid analogues, NBD-PE (phosphatidylethanolamine), NBD-PC (phosphatidylcholine) and NBD-PS (phosphatidylserine), to demonstrate that Cdr1p and its other homologues, Cdr2p and Cdr3p, belonging to the ATP-binding cassette (ABC) superfamily behave as general phospholipid translocators. Interestingly, CDR1 and CDR2, whose overexpression leads to azole resistance in C. albicans, elicit in-to-out transbilayer phospholipid movement, while CDR3, which is not involved in drug resistance, carries out-to-in translocation of phospholipids between the two monolayers of plasma membrane. Cdr1p, Cdr2p and Cdr3p could be further distinguished on the basis of their sensitivities to different inhibitors. For example, the in-to-out activity associated with Cdr1p and Cdr2p is energy-dependent and sensitive to sulphydryl blocking agents such as N-ethylmaleimide (NEM) and cytoskeleton disrupting agent cytochalasin E, while Cdr3p-associated out-to-in activity is energydependent but insensitive to NEM and cytochalasin E. We found that certain drugs, such as fluconazole, cycloheximide and miconazole, to which Cdr1p confers resistance could also affect in-to-out transbilayer movement of NBD-PE, while the same drugs had no effect on Cdr3p-mediated out-to-in translocation of NBD-PE. The ineffectiveness of these drugs to affect Cdr3p mediated out-to-in phospholipid translocation further confirms the inherent difference in the directionality of phospholipid translocation between these pumps. Notwithstanding the role of some of the Cdrps in drug resistance, this study clearly demonstrates that these ABC transporters of C. albicans are phospholipid translocators and this function could represent one of the physiological functions of such large family of proteins.

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Dipole moment change of NBD group upon excitation studied using solvatochromic and quantum chemical approaches: Implications in membrane research

Cited by 121 publications

References 10 publications

First observation of 3D aggregates in a single-component Langmuir film below the equilibrium spreading pressure

First observation of 3D aggregates in a single-component Langmuir film below the equilibrium spreading pressure

Organization and Dynamics of Membrane Probes and Proteins Utilizing the Red Edge Excitation Shift

ABC transporters Cdr1p, Cdr2p and Cdr3p of a human pathogen Candida albicans are general phospholipid translocators

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