On the significance of the fourth-rank orientational order parameter of fluorophores in membranes

Pottel, Hans; Herreman, W.; Meer, B. Wieb van der; Ameloot, Marcel

doi:10.1016/0301-0104(86)85115-1

Cited by 85 publications

(86 citation statements)

References 20 publications

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“…The relation between (P2> and (P4> is best described by a P4-distribution model, indicating that the interaction energy of the DPH-propionic acid probe is proportional to/'4 (cos fl), where fl is the angle between the probe molecule and the normal to the bilayers. This is in agreement with results obtained by Pottel et al (1986) for DPH molecules in the phospholipids DMPC and DPPC.…”

Section: Diffusion Coefficientsupporting

confidence: 93%

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A small protein in model membranes: a time-resolved fluorescence and ESR study on the interaction of M13 coat protein with lipid bilayers

et al. 1992

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Model membranes with unsaturated lipid chains containing various amounts of M13 coat protein in the alpha-helical form were studied using time-resolved fluorescence and ESR spectroscopy. The lipid-to-protein (L/P) ratios used were > 12 to avoid protein-protein contacts and irreversible aggregation leading to beta-polymeric coat protein. In the ESR spectra of the 12-SASL probe in dioleoyl phosphatidylcholine (DOPC) bilayers no second protein induced component is observed upon incorporation of M13 coat protein. However, strong effects are detected on the ESR lineshapes upon changing the protein concentration. The ESR lineshapes are simulated by assuming a fixed ratio between the parallel (D parallel) and perpendicular (D perpendicular) diffusion coefficients of 4, and an order parameter equal to zero. It is found that increasing the protein concentration from L/P infinity to L/P 15 results in a decrease of the rotational diffusion coefficient D perpendicular from 3.4 x 10(7) to 1.9 x 10(7) s-1. In the time-resolved fluorescence experiments with DPH-propionic acid as a probe, it is observed that increasing the M13 coat protein concentration causes an increase of the two fluorescent lifetimes, indicating an increase in bilayer order. Analysis of the time-resolved fluorescence anisotropy decay allows one to quantitatively determine the order parameters and , and the rotational diffusion coefficient D perpendicular of the fluorescent probe. The order parameters and increase from 0.34 to 0.55 and from 0.59 to 0.77, respectively, upon adding M13 coat protein to DOPC bilayers with an L/P ratio of 35.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Diffusion Coefficientsupporting

confidence: 93%

“…The initial anisotropy, r (0), depends on the angle between the absorption and emission moments. This parameter was fixed to a value of 0.39 as has been obtained by other authors (Ameloot et al 1984;Pottel et al 1986). …”

Section: Methodsmentioning

confidence: 99%

A small protein in model membranes: a time-resolved fluorescence and ESR study on the interaction of M13 coat protein with lipid bilayers

et al. 1992

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“…Findings of large (P4) have recently been reported for DPH in phospholipid model membranes [67]. These large values are compatible, for example with the P4 model potential described in [68].…”

Section: Resultssupporting

confidence: 64%

Time resolved fluorescence depolarization in a nematic liquid crystal

et al. 1987

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A time dependent fluorescence depolarization experiment is reported and fully analysed for the first time for a probe dissolved in an aligned nematic liquid crystal. We have investigated the popular dye all trans 1,6 diphenyl hexatriene in the transparent mesophase mixture ZLI-1167 at a series of temperatures within the nematic and isotropic range. The probe order parameter (P2) and perpendicular rotational diffusion coefficient have been determined, together with the fluorescence lifetime ZF in the liquid crystal and isotropic phase. This information is extracted applying a previously proposed theory for rotational fluorescence depolarization in a mesophase , Molec. Phys., 38, 1813 and introducing a global variant of the target analysis deconvolution procedure presented earlier (ARCIONI, A., and ZANNONI) C., 1984, Chem. Phys., 88, 113). Our results demonstrate the possibility of employing fluorescence depolarization as a useful technique for investigating aligned mesophases. IntroductionThe theory needed to interpret time resolved fluorescence depolarization experiments [1, 2] in a liquid crystal [3] has been around for some time now [4]. This theory gives a molecular interpretation to time dependent fluorescence polarization intensities by assuming molecular reorientation to be the dominant depolarizing mechanism. The theoretical intensities are then expressed in terms of static and dynamic quantities, i.e. orientational order parameters and correlation functions [4]. For the simplest case of a rigid probe with effective cylindrical symmetry dissolved in a uniaxial mesophase the orientational order parameters are given by the infinite set of Legendre polynomial averages (PL) = (PL( cos fl)), where fl is the angle between the cylinder axis of the molecule and that of the mesophase [5]. A fluorescence depolarization decay experiment can yield in favourable conditions the first two non-trivially vanishing order parameters, i.e. (P2) and (P4) I'4, 6]. What can be obtained in practice from a certain experiment is predicted to depend on the relative times scales of the fluoresence decay and reorientation process ZF and ZR. Let us consider, to be specific, a rod-like probe molecule [7] with absorption and emission transition moments p and ~ parallel to the long molecular axis. In this case the fourth rank order parameter (P4) for the probe can be obtained when the fluorescence time ZF is much shorter than the long axis correlation time ~o. On the other hand if ZV is much longer than Zo, so that the photoselected molecules have enough time to relax to orientational equilibrium, only the second rank Legendre polynomial average (P2) can be reliably obtained. The maximum amount of information can be extracted from experiments where the time dependence of fluorescence depolarization is followed. There, in fact, orientational correlation functions Downloaded by [McMaster University] at 02:

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“…However, the distribution of orientation can be estimated from P 2 and P 4 by calculating the so-called most probable orientation function, N mp (h), using the information entropy theory. [39][40][41][42] Some results have shown that the distributions of orientation of the B. mori and S. c. ricini fibers are basically identical and broader than that of the dragline of N. edulis. 26 As an illustration, the function N mp (h) as evaluated from the decomposition of the amide I band is shown in Figure 3 for the b-sheet component of the dragline.…”

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confidence: 99%

Structure of silk by raman spectromicroscopy: From the spinning glands to the fibers

et al. 2011

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Raman spectroscopy has long been proved to be a useful tool to study the conformation of protein‐based materials such as silk. Thanks to recent developments, linearly polarized Raman spectromicroscopy has appeared very efficient to characterize the molecular structure of native single silk fibers and spinning dopes because it can provide information relative to the protein secondary structure, molecular orientation, and amino acid composition. This review will describe recent advances in the study of the structure of silk by Raman spectromicroscopy. A particular emphasis is put on the spider dragline and silkworm cocoon threads, other fibers spun by orb‐weaving spiders, the spinning dope contained in their silk glands and the effect of mechanical deformation. Taken together, the results of the literature show that Raman spectromicroscopy is particularly efficient to investigate all aspects of silk structure and production. The data provided can lead to a better understanding of the structure of the silk dope, transformations occurring during the spinning process, and structure and mechanical properties of native fibers. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 322–336, 2012.

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On the significance of the fourth-rank orientational order parameter of fluorophores in membranes

Cited by 85 publications

References 20 publications

A small protein in model membranes: a time-resolved fluorescence and ESR study on the interaction of M13 coat protein with lipid bilayers

A small protein in model membranes: a time-resolved fluorescence and ESR study on the interaction of M13 coat protein with lipid bilayers

Time resolved fluorescence depolarization in a nematic liquid crystal

Structure of silk by raman spectromicroscopy: From the spinning glands to the fibers

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