Nanothin films of tubular oligopeptides: monolayers and Langmuir-Blodgett films of β4.4-helices with surface-pressure-dependent orientation

Römer, D.; Lorenzi, Gian Paolo; Weisenhorn, A. L.

doi:10.1016/0040-6090(94)90068-x

Cited by 4 publications

(4 citation statements)

References 11 publications

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“…These authors found that, at low surface pressures, Langmuir films of the peptide lie flat at the air ± water interface, while at higher pressures the peptide reorients itself with its helical axis perpendicular to the surface of the water. [170] Atomic force microscopy (AFM), ellipsometry, and grazing angle IR measurements of Langmuir ± Blodgett films supported on ultraflat silicon surfaces corroborated these conclusions. [171] …”

Section: B-helical Biosensorsmentioning

confidence: 70%

Self-Assembling Organic Nanotubes

Bong

Clark

Granja

et al. 2001

Angew. Chem. Int. Ed.

1,076

130

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Section: B-helical Biosensorsmentioning

confidence: 70%

Self-Assembling Organic Nanotubes

Bong

Clark

Granja

et al. 2001

Angew. Chem. Int. Ed.

1,076

130

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“…This behavior is in some respects related to observations made with bolaamphiphiles, where reducing the symmetry by making the two headgroups different changes their organization at the interface. Interestingly, a reorientation of the molecules with respect to the interface can also be found for some helical peptides …”

Section: Discussionmentioning

confidence: 89%

Influence of the Position of the Hydrophilic Group on the Monolayer Properties of Rigid Amphiphiles with Laterally Attached Headgroups

1999

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The π/A isotherms of rodlike 4,4‘ ‘-didecyloxy-p-terphenyl derivatives incorporating hydrophilic 1,2-diol groups in different lateral positions were recorded with dependence on the temperature, and the thin films were investigated by Brewster angle microscopy. Depending on the position of the hydrophilic groups and on the type of spacer between the hydrophilic group and the rigid core, different types of isotherms with different temperature dependences have been found. Two sharp breaks separated by a large plateau occur along the π/A isotherms of the 2-substituted and 2‘-substituted compounds. In the plateau region a defined formation of a triple layer is proposed. For the 3-substituted compounds with a peripheral position of the hydrophilic groups, the type of isotherm largely depends on the type and the length of the spacer unit between the hydrophilic group and the rigid core. Two transition regions can be found in the slope of their isotherms. A tentative model of the organization of these molecules with dependence on the lateral pressure is proposed. Accordingly, the first transition is attributed to a transition of the rigid cores from a flat arrangement on the surface to a tilted arrangement. In the second transition region either formation of a defined triple layer (short spacer) or transition to a more densely packed monomolecular film with the rigid cores arranged parallel or tilted to the surface normal (long polyether chains) should take place. If the hydrophilic groups are coupled via lipophilic alkyl chains, the molecules are organized immediately after spreading and π/A isotherms similar to those of amphiphiles with terminal hydrophilic groups have been found. Thus, by slight changes of the molecular structure completely different supermolecular organizations at the water surface can be realized.

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“…Bei Voruntersuchungen, die die Herstellung ionenselektiver Membranen zum Ziel hatten, überprüften Weisenhorn und Lorenzi dünne Filme des synthetischen β 4.4 ‐Helix‐Oligopeptids Boc‐ D ‐Val‐( L ‐Val‐ D ‐Val) 7 ‐OMe. Bei niedrigem Spreitungsdruck fanden sie, dass Langmuir‐Filme des Peptids flach an der Luft‐Wasser‐Grenzschicht liegen, während sich das Peptid bei höherem Spreitungsdruck so ausrichtet, dass seine Helixachse senkrecht auf der Wasseroberfläche steht 170. Kraftfeldmikroskopie (AFM), Ellipsometrie und Streifwinkel‐IR‐Messungen an Langmuir‐Blodgett‐Filmen, die auf ultraflachen Siliconoberflächen aufgebracht waren, untermauerten diese Schlussfolgerungen 171…”

Section: Mögliche Anwendungenunclassified

Sequestration of connexin43 in the early endosomes: An early event of Leydig cell tumor progression

Segretain

Decrouy

Dompierre

et al. 2003

Molecular Carcinogenesis

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Connexins form gap junction channels that allow intercellular communication between neighboring cells. Compelling evidence has revealed that Cx are tumor-suppressor genes and reduced Cx expression has been related with uncontrolled cell growth in tumors and transformed cells. In the present study, we addressed Cx transcriptional and posttranscriptional regulations during the earlier stage of testicular tumors confined to Leydig cells in a transgenic mice model. In situ hybridization indicated that connexin43 (Cx43) mRNA was highly expressed either at early tumorogenesis (3 m) characterized by intense proliferation of Leydig cells, or at advanced tumorogenesis (6-7 m) when tumor cells completely invaded the testis. In contrast, Cx43 protein analyzed by Western blotting or classic immunohistochemical analyses was present at the beginning of tumor progression, but was dramatically reduced as tumor advanced. Application of high-resolution deconvolution microscopy to testis sections demonstrates that cells that proliferate exhibited an aberrant cytoplasmic Cx43 localization, in contrast to the expected plasma membrane Cx43 localization in normal Leydig cells. Dual immunofluorescence labeling with specific markers of cellular compartments shows that cytoplasmic Cx43 signal was mainly sequestered within early endosomes. Altogether, this study provides the first evidence that impaired Cx43 trafficking in endosomes is an early event associated with uncontrolled cell proliferation that could serve as a neoplastic marker.

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Nanothin films of tubular oligopeptides: monolayers and Langmuir-Blodgett films of β4.4-helices with surface-pressure-dependent orientation

Cited by 4 publications

References 11 publications

Self-Assembling Organic Nanotubes

Self-Assembling Organic Nanotubes

Influence of the Position of the Hydrophilic Group on the Monolayer Properties of Rigid Amphiphiles with Laterally Attached Headgroups

Sequestration of connexin43 in the early endosomes: An early event of Leydig cell tumor progression

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