Nanostructure of Fullerene-Bearing Artificial Lipid Monolayer on Water Surface by in Situ X-ray Reflectometry

Biological membrane is composed of lipid molecules, because of its fluidity, it is possible to carry out physiological functions. Therefore, it is important to study the hydrodynamic properties of membranes toward understanding its function. Here, we observed the dynamical behavior of a lipid monolayer on the water surface under Marangoni flow. By using X-ray reflectometry, we obtained the tilt angle of the hydrocarbon chains of the lipid at different surface pressures. Comparing them with the dynamical surface pressure under Marangoni flow, it was found that the lipid molecules in rotational rather than translational motion. At low surface pressure, the molecular tilt angle is reduced by 20 degrees, even though the molecular area is reduced by at most 10%.

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The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071107 ◽

1973 ◽

Vol 31 ◽

pp. 132-133 ◽

Cited By ~ 1

Author(s):

R. E. Herfert

Keyword(s):

Surface Characterization ◽

Analytical Techniques ◽

X Ray Diffraction ◽

Depth Of Penetration ◽

X Ray ◽

The Past ◽

Transmission Electron ◽

Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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Structure of rattlesnake venom lectin determined by single particle high-resolution electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162776 ◽

1996 ◽

Vol 54 ◽

pp. 62-63

Author(s):

Peter D. Moisiuk ◽

Daniel R. Beniac ◽

Ross A. Ridsdale ◽

Martin Young ◽

Bhushan Nagar ◽

...

Keyword(s):

High Resolution Electron Microscopy ◽

Lipid Monolayer ◽

Outer Diameter ◽

X Ray Diffraction ◽

Single Particles ◽

Crotalus Atrox ◽

3D Reconstructions ◽

X Ray ◽

Rattlesnake Venom ◽

Covalently Linked

Venom from the rattlesnake Crotalus atrox contains a mixture of enzymes that induce a localized effect leading to hemorrhaging, necrosis and edema. As a member of the crotalid family of snake venoms, Crotalus atrox venom contains a C-type lectin that will agglutinate blood cells in a Ca2+-dependent fashion. The lectin is a hydrophilic protein, consisting of two covalently linked, 135 amino acid residues, identical subunits that are rich in aspartic acid, glutamic acid and lysine. Sequence homology with known carbohydrate recognition domains (CRDs) indicates that rattlesnake venom lectin (RSLV) contains a CRD motif that is not linked to accessory domains. Preliminary X-ray diffraction and sedimentation analysis has indicated that lectin from Crotalus atrox forms decamers composed of two five-fold symmetric pentamers. Single particles of RSVL imaged at – 171°C displayed two distinct orientations on the specimen support (Figure a) following incubation in a crystallization Teflon well, coated with a lipid monolayer consisting of phosphatidylcholine and monosialoganglioside. When lying in an end-on orientation, the lectin exhibited a “pentagonal ring” with an outer diameter of 6.7 nm and an inner hollow core of 1.7 nm. A side orientation was also seen, whereby a thickness of 5.8 nm was measured for the lectin. Image processing of 2280 single particles placed in 100 classes (Figure b) led to 3D reconstructions of RSVL (Figure c). Density limited 3D reconstructions showed the lectin to be made of two five-fold symmetrical rings covalently linked between the five subunits that constitute each ring of this homodimer. These results are consistent with sedimentation and preliminary X-ray diffraction analysis on the shape of RSVL and provide the framework for structural verification by 2D electron crystallography.

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Biophysics (and sociology) of ceramides.

Biochemical Society Symposium ◽

10.1042/bss0720177 ◽

2005 ◽

Vol 72 ◽

pp. 177-188 ◽

Cited By ~ 28

Author(s):

Félix M. Goñi ◽

F-Xabier Contreras ◽

L-Ruth Montes ◽

Jesús Sot ◽

Alicia Alonso

Keyword(s):

Cell Biology ◽

Positive Curvature ◽

Acyl Chain ◽

Cell Signalling ◽

Hexagonal Structure ◽

Lipid Monolayer ◽

Flip Flop ◽

Long Chain ◽

Bilayer Permeability

In the past decade, the long-neglected ceramides (N-acylsphingosines) have become one of the most attractive lipid molecules in molecular cell biology, because of their involvement in essential structures (stratum corneum) and processes (cell signalling). Most natural ceramides have a long (16-24 C atoms) N-acyl chain, but short N-acyl chain ceramides (two to six C atoms) also exist in Nature, apart from being extensively used in experimentation, because they can be dispersed easily in water. Long-chain ceramides are among the most hydrophobic molecules in Nature, they are totally insoluble in water and they hardly mix with phospholipids in membranes, giving rise to ceramide-enriched domains. In situ enzymic generation, or external addition, of long-chain ceramides in membranes has at least three important effects: (i) the lipid monolayer tendency to adopt a negative curvature, e.g. through a transition to an inverted hexagonal structure, is increased, (ii) bilayer permeability to aqueous solutes is notoriously enhanced, and (iii) transbilayer (flip-flop) lipid motion is promoted. Short-chain ceramides mix much better with phospholipids, promote a positive curvature in lipid monolayers, and their capacities to increase bilayer permeability or transbilayer motion are very low or non-existent.

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In Situ X-Ray Absorption Studies of the Electrochemical Reduction of Hydroxocobalamin

Journal de Physique IV (Proceedings) ◽

10.1051/jp4/1997116 ◽

1997 ◽

Vol 7 (C2) ◽

pp. C2-619-C2-620 ◽

Cited By ~ 1

Author(s):

M. Giorgett ◽

I. Ascone ◽

M. Berrettoni ◽

S. Zamponi ◽

R. Marassi

Keyword(s):

Electrochemical Reduction ◽

X Ray ◽

Absorption Studies ◽

X Ray Absorption

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In-situ investigation by X-ray diffraction and wafer curvature of phase formation and stress evolution during metal thin film – silicon reactions

Zeitschrift für Kristallographie Supplements ◽

10.1524/zksu.2007.2007.suppl_26.81 ◽

2007 ◽

Vol 2007 (suppl_26) ◽

pp. 81-89

Author(s):

O. Thomas

Keyword(s):

Thin Film ◽

Phase Formation ◽

Stress Evolution ◽

X Ray Diffraction ◽

X Ray ◽

Wafer Curvature ◽

Thin Film Silicon ◽

Metal Thin Film ◽

In Situ Investigation

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A Revised O2 Reduction Model in Li-O2 Batteries as Revealed by in Situ Small Angle X-Ray Scattering

10.26434/chemrxiv.11447775.v1 ◽

2019 ◽

Author(s):

Christian Prehal ◽

Aleksej Samojlov ◽

Manfred Nachtnebel ◽

Manfred Kriechbaum ◽

Heinz Amenitsch ◽

...

Keyword(s):

Small Angle ◽

Wide Angle ◽

Reduction Mechanism ◽

Reduction Model ◽

X Ray ◽

X Ray Scattering ◽

O2 Reduction ◽

Ray Scattering

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>

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