Lipid headgroups mediate organization and dynamics in bilayers

Greenough, Kelly P.; Blanchard, G. J.

doi:10.1016/j.saa.2008.08.002

Cited by 6 publications

(9 citation statements)

References 59 publications

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“…This assignment is based on the consideration that the PO 2 À groups are involved in different inter and intramolecular associations. [17,18,22,45,46] Theoretical predictions concerning the conformations adopted by the isolated…”

Section: Resultsmentioning

confidence: 99%

“…Then, the main component bands are associated to vibrations belonging to groups located in the polar region of the membrane (PO 2 − and glycerol ―CH 2 OH). This assignment is based on the consideration that the PO 2 − groups are involved in different inter and intramolecular associations . Theoretical predictions concerning the conformations adopted by the isolated charged molecule [CH 3 ―O―P(O) 2 ―O―CH 2 ―CHOH―CH 2 OH] − showed the preference for a geometry with one of the PO bonds associated by hydrogen bond with the terminal OH group of the flexible glycerol chain .…”

Section: Resultsmentioning

confidence: 99%

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Raman spectroscopy study of the interaction of 3,5,3′‐triiodo‐L‐thyronine with phosphatidylglycerol lipid bilayers

Morales

Juárez

Alvarez

2015

J Raman Spectroscopy

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A Raman spectroscopic study of anionic model membranes and their structural alterations exerted by a relatively small biomolecule, such as the hormone 3,5,3′-triiodo-L-thyronine (T3), is presented. Spectral differences between pure dipalmitoylphosphatidylglycerol (DPPG) multilamellar vesicles and DPPG-T3 mixture and between pure dilauroylphosphatidylglycerol (DLPG) and DLPG-T3 mixture were evaluated in order to determine the response of lipid membranes in gel and liquid-crystalline phases to the hormone incorporation. Density functional theory (DFT) calculations support the band analysis of the complex 1150-1050 cm À1 Raman region. Geometry optimizations and vibrational behaviors of a model charged molecule that mimics the phosphatidylglycerol lipid moiety in solvated state were taken into account for the spectral interpretation of this specific region. The anionic nature of the lipid polar head plays an important role in the interaction with the hormone, as is evidenced by the C¼O and PO 2 À stretching bands. In addition, the differential penetration of T3 into the hydrophobic region of the membranes shows to be dependent on the lipid phase. The spectral data were compared with those previously obtained for zwitterionic membranes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Raman spectroscopy study of the interaction of 3,5,3′‐triiodo‐L‐thyronine with phosphatidylglycerol lipid bilayers

Morales

Juárez

Alvarez

2015

J Raman Spectroscopy

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“…It is the functional form and the time constant(s) associated with the decay of R ( t ) that are related to the local environment of the reorienting molecule. Chuang and Eisenthal developed a model for fluorescence anisotropy decay that provides a means of interpreting anisotropy decay functions containing up to five exponential components. ,,− Despite this potential for complexity, one or two decays are the functional forms observed most commonly. For the excitation and emission transition moments oriented parallel to one another, along the long axis in the chromophore π-system plane, reorientation of the chromophore as a prolate rotor ( D x > D y = D z ) gives rise to a single exponential decay of R ( t ) (eq ), and reorientation as an oblate rotor ( D z > D x = D y ) produces a two-component R ( t ) function, as described by eq .…”

Section: Resultsmentioning

confidence: 99%

“…Resorufin reorients as a prolate rotor in small polar solvents such as methanol and acetonitrile and has been shown to exhibit varying degrees of Na + dissociation in the butanols . The NBD chromophore is used widely as a probe and has been attached to phospholipids or cholesterol for the interrogation of lipid bilayer structure and dynamics. − NBDHA (Figure b) has a hexanoic acid pendant functionality and reorients as a prolate rotor in solvents such as n -alcohols, acetonitrile, DMF, and DMSO . There is a limited range of solvents in which both chromophores have been studied, and those data are compiled in Table .…”

Section: Resultsmentioning

confidence: 99%

Solvent-Dependent Changes in Molecular Reorientation Dynamics: The Role of Solvent−Solvent Interactions

2010

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We report on the rotational diffusion dynamics of two different chromophores, resorufin and 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoic acid (NBDHA) in water and N-octyl-2-pyrrolidone (NOP) solvents. We measure the induced orientational anisotropy function, R(t), using time-correlated single photon counting. Our data show that both chromophores exhibit single exponential anisotropy decays in aqueous solution and two-component exponential anisotropy decays in NOP. The change of the anisotropy decay functionality indicates that the effective rotor shape swept out by solute rotational motion is different in the two solvents. We interpret these findings in the context of Chuang and Eisenthal's theory of fluorescence depolarization by rotational diffusion. The similarity in the behavior of the two different chromophores in these solvent systems points to solvent-solvent interactions and local organization as the dominant factors in mediating motional dynamics.

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“…Supported bilayers are amenable to electrochemical interrogation if the solid support is conductive. For free-standing bilayer structures such as unilamellar vesicles, electrochemical characterization is not possible, but spectroscopic methods are capable of providing significant insight into local organization. − NMR − and neutron scattering studies have proven invaluable, for example, in elucidating the details of phase transitions and intermolecular interactions in bilayer structures. One advantage of NMR studies is that they do not require the incorporation of a structurally perturbative probe into the bilayer.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Sensitivity of Lipid Headgroup-Bound Chromophores to Their Local Environment

Setiawan

Blanchard

2012

J. Phys. Chem. B

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We report on the steady state and time-resolved fluorescence behavior of the chromophore 1,2-dimiryristoyl-sn-glycero-3-phosphoethanolamine-N-lissamine rhodamine B sulfonyl ammonium salt (SR-DMPE) in a series of solution phase and lipid bilayer environments. The issue of interest is whether or not the lipid headgroup-bound chromophore is sensitive to its local environment under conditions where vesicles have not been formed in lipid-containing mixtures and where unilamellar vesicles have been formed by extrusion. Our data point to the strong interaction of SR-DMPE with 1,2-dimirystoyl-sn-glycero-phosphocholine (DMPC) in solution whether or not the solution has undergone extrusion. The amount of SR-DMPE in the lipid-containing systems affects both the steady state and time-resolved spectroscopic response. Excitation of the chromophore to the S(2) state deposits sufficient excess energy into the system to influence its rotational diffusion dynamics, demonstrating significant interactions between SR-DMPE and DMPC. Comparison of SR-DMPE reorientation dynamics in DMPC-containing solutions with corresponding data on SR-DMPE in aqueous solution indicates that the lipids impose a restrictive local environment on the chromophore that is a factor of ca. 10 more viscous than an aqueous environment. The similarity of the reorientation data in all DMPC-containing solutions suggests that SR-DMPE is a local probe that is not sensitive to longer range organization.

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Lipid headgroups mediate organization and dynamics in bilayers

Cited by 6 publications

References 59 publications

Raman spectroscopy study of the interaction of 3,5,3′‐triiodo‐L‐thyronine with phosphatidylglycerol lipid bilayers

Raman spectroscopy study of the interaction of 3,5,3′‐triiodo‐L‐thyronine with phosphatidylglycerol lipid bilayers

Solvent-Dependent Changes in Molecular Reorientation Dynamics: The Role of Solvent−Solvent Interactions

Evaluating the Sensitivity of Lipid Headgroup-Bound Chromophores to Their Local Environment

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