Surface and Spectroscopic Properties of Photosystem II Core Complex at the Nitrogen/Water Interface

Gallant, Judith; Lavoie, Hugo; Tessier, Alain; Munger, G.; Leblanc, Roger M.; Salesse, Christian

doi:10.1021/la971276w

Cited by 20 publications

(25 citation statements)

References 61 publications

(65 reference statements)

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“…14 The fluorescence micrographs of the RhC 18 monolayer at the air/water interface were obtained with the epifluorescence microscope described elsewhere. 15 The micrographs were taken in different regions of the π-A isotherm.…”

Section: Methodsmentioning

confidence: 99%

Microscopic Organization of Long-Chain Rhodamine Molecules in Monolayers at the Air/Water Interface

et al. 2002

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The monolayer behavior of a rhodamine derivative with two C 18 aliphatic chains attached to the nitrogen atoms of the xanthene ring system (RhC 18 ) was studied by epifluorescence microscopy, second-harmonic generation (SHG), and absorption and fluorescence spectroscopy. The isotherm of RhC 18 exhibits a plateau which, presumably, corresponds to a slow collapse of the monolayer. As observed by epifluorescence microscopy, the RhC 18 monolayer remained homogeneous for a large range of molecular areas, and an abrupt change in the monolayer morphology occurred at the end of the surface pressure isotherm. Spectroscopic data showed that both fluorescent J-aggregates and nonfluorescent H-aggregates with a coplanar-inclined configuration were formed within the RhC 18 monolayer upon compression. The orientational SHG measurements revealed that, in the expanded region of the isotherm, the RhC 18 chromophore was oriented in a way where its xanthene plane made an angle of 36°with respect to the interface. The azimuthal angle SHG measurements revealed that compression induced an anisotropic arrangement of the S 0 -S 1 transition moment of RhC 18 chromophores perpendicular to the compression direction. At the end of the isotherm prior to and after the collapse point, the film possessed a fairly regular structure characterized by a C 2V symmetry packing and a long-range order in the parallel alignment of the RhC 18 chromophores. Microscopic organization of the RhC 18 molecules in monolayers is discussed.

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Section: Methodsmentioning

confidence: 99%

Microscopic Organization of Long-Chain Rhodamine Molecules in Monolayers at the Air/Water Interface

et al. 2002

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“…This reduction was attributed to the fact that unfolded ␤-sheets occupy a larger area at the interface than ␣-helices. Indeed, the measurement of surface pressure-area isotherms showed that incubation of PS II CC at 0.6 mN/m leads to an increase of 1.7-4.3 in molecular area compared with when it is spread at 5.7 mN/m (Gallant et al, 1998). The PM-IRRAS signal is thus lowered as the number of amino acid residues per surface area is reduced.…”

Section: Formation Of ␤-Sheetsmentioning

confidence: 99%

Polarization-Modulated Infrared Spectroscopy and X-Ray Reflectivity of Photosystem II Core Complex at the Gas-Water Interface

Gallant

Desbat

Vaknin

et al. 1998

Biophysical Journal

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The state of photosystem II core complex (PS II CC) in monolayer at the gas-water interface was investigated using in situ polarization-modulated infrared reflection absorption spectroscopy and x-ray reflectivity techniques. Two approaches for preparing and manipulating the monolayers were examined and compared. In the first, PS II CC was compressed immediately after spreading at an initial surface pressure of 5.7 mN/m, whereas in the second, the monolayer was incubated for 30 min at an initial surface pressure of 0.6 mN/m before compression. In the first approach, the protein complex maintained its native alpha-helical conformation upon compression, and the secondary structure of PS II CC was found to be stable for 2 h. The second approach resulted in films showing stable surface pressure below 30 mN/m and the presence of large amounts of beta-sheets, which indicated denaturation of PS II CC. Above 30 mN/m, those films suffered surface pressure instability, which had to be compensated by continuous compression. This instability was correlated with the formation of new alpha-helices in the film. Measurements at 4 degreesC strongly reduced denaturation of PS II CC. The x-ray reflectivity studies indicated that the spread film consists of a single protein layer at the gas-water interface. Altogether, this study provides direct structural and molecular information on membrane proteins when spread in monolayers at the gas-water interface.

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“…Moreover, there is a direct thermodynamic relationship between bilayers and monolayers [126,127]. In addition, a large number of spectroscopic (UV-visible absorption [128][129][130][131][132][133][134], fluorescence [128,[131][132][133][134][135][136], and vibrational [137][138][139][140][141][142][143], (see [120,[144][145][146][147][148][149][150][151][152] for a review)), microscopic (Brewster angle [153,154] and fluorescence [155][156][157], (see [158][159][160][161][162][163][164] for a review)), and different additional physical methods [165][166][167]…”

Section: Monolayers As a Model Membrane To Study Hydrophobic Transmemmentioning

confidence: 99%

Comparison between the behavior of different hydrophobic peptides allowing membrane anchoring of proteins

Lhor¹,

Bernier²,

Horchani³

et al. 2014

Advances in Colloid and Interface Science

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Membrane binding of proteins such as short chain dehydrogenases reductases or tail-anchored proteins relies on their N-and/or C-terminal hydrophobic transmembrane segment. In this review, we propose guidelines to characterize such hydrophobic peptide segments using spectroscopic and biophysical measurements. The secondary structure content of the C-terminal peptides of retinol dehydrogenase 8, RGS9-1 anchor protein, lecithin retinol acyl transferase, and of the N-terminal peptide of retinol dehydrogenase 11 has been deduced by prediction tools from their primary sequence as well as by using infrared or circular dichroism analyses. Depending on the solvent and the solubilization method, significant structural differences were observed, often involving α-helices. The helical structure of these peptides was found to be consistent with their presumed membrane binding. Langmuir monolayers have been used as membrane models to study lipidpeptide interactions. The values of maximum insertion pressure obtained for all peptides using a monolayer of 1,2-dioleoyl-sn-glycero-3-phospho-ethanolamine (DOPE) are larger than the estimated lateral pressure of membranes, thus suggesting that they bind membranes. Polarization modulation infrared reflection absorption spectroscopy has been used to determine the structure and orientation of these peptides in the absence and in the presence of a DOPE monolayer. This lipid induced an increase or a decrease in the organization of the peptide secondary structure. Further measurements are necessary using other lipids to better understand the membrane interactions of these peptides.

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Surface and Spectroscopic Properties of Photosystem II Core Complex at the Nitrogen/Water Interface

Cited by 20 publications

References 61 publications

Microscopic Organization of Long-Chain Rhodamine Molecules in Monolayers at the Air/Water Interface

Microscopic Organization of Long-Chain Rhodamine Molecules in Monolayers at the Air/Water Interface

Polarization-Modulated Infrared Spectroscopy and X-Ray Reflectivity of Photosystem II Core Complex at the Gas-Water Interface

Comparison between the behavior of different hydrophobic peptides allowing membrane anchoring of proteins

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