scholarly journals Recrystallization of tubules from natural lotus (Nelumbo nucifera) wax on a Au(111) surface

2011 ◽  
Vol 2 ◽  
pp. 261-267 ◽  
Author(s):  
Sujit Kumar Dora ◽  
Klaus Wandelt
Keyword(s):  
Physical Properties ◽  
Single Crystal ◽  
Self Assembly ◽  
Nelumbo Nucifera ◽  
The Self ◽  
Tubule Formation ◽  
First Results ◽  
Substrate Properties ◽  
Lotus Leaves ◽  
Natural Wax

We present here the first results on the self-assembly of tubules of natural wax from lotus leaves on a single crystal Au(111) surface. A comparison of the tubule growth on Au(111) to that on HOPG is discussed. Although the tubule formation on both Au(111) and HOPG takes place on an intermediate wax film which should mask the substrate properties, the tubule orientations differ. In contrast to a vertical tubule orientation on HOPG, the tubules lie flat on Au(111). Taking into account the physical properties of HOPG and Au(111), we put forward a hypothesis which can explain the different tubule orientations on both substrates.

scholarly journals Modification of a Single Atom Affects the Physical Properties of Double Fluorinated Fmoc-Phe Derivatives

2021 ◽  
Vol 22 (17) ◽  
pp. 9634
Author(s):  
Moran Aviv ◽  
Dana Cohen-Gerassi ◽  
Asuka A. Orr ◽  
Rajkumar Misra ◽  
Zohar A. Arnon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physical Properties ◽  
Self Assembly ◽  
Deep Understanding ◽  
Building Blocks ◽  
The Self ◽  
Single Atom ◽  
Supramolecular Organization ◽  
Assembly Process ◽  
Wide Range

Supramolecular hydrogels formed by the self-assembly of amino-acid based gelators are receiving increasing attention from the fields of biomedicine and material science. Self-assembled systems exhibit well-ordered functional architectures and unique physicochemical properties. However, the control over the kinetics and mechanical properties of the end-products remains puzzling. A minimal alteration of the chemical environment could cause a significant impact. In this context, we report the effects of modifying the position of a single atom on the properties and kinetics of the self-assembly process. A combination of experimental and computational methods, used to investigate double-fluorinated Fmoc-Phe derivatives, Fmoc-3,4F-Phe and Fmoc-3,5F-Phe, reveals the unique effects of modifying the position of a single fluorine on the self-assembly process, and the physical properties of the product. The presence of significant physical and morphological differences between the two derivatives was verified by molecular-dynamics simulations. Analysis of the spontaneous phase-transition of both building blocks, as well as crystal X-ray diffraction to determine the molecular structure of Fmoc-3,4F-Phe, are in good agreement with known changes in the Phe fluorination pattern and highlight the effect of a single atom position on the self-assembly process. These findings prove that fluorination is an effective strategy to influence supramolecular organization on the nanoscale. Moreover, we believe that a deep understanding of the self-assembly process may provide fundamental insights that will facilitate the development of optimal amino-acid-based low-molecular-weight hydrogelators for a wide range of applications.

Co-assembly of helical β3-peptides: a self-assembled analogue of a statistical copolymer

2017 ◽  
Vol 89 (12) ◽  
pp. 1809-1816 ◽  
Author(s):  
Claire Buchanan ◽  
Christopher J. Garvey ◽  
Patrick Perlmutter ◽  
Adam Mechler
Keyword(s):  
Amino Acids ◽  
Physical Properties ◽  
Self Assembly ◽  
Unnatural Amino Acids ◽  
The Self ◽  
Microscopy Imaging ◽  
Wide Range ◽  
Self Assembled ◽  
Unnatural Peptides ◽  
Natural Amino Acids

AbstractUnnatural peptide self-assembly offers the means to design hierarchical nanostructures of controlled geometries, chemical function and physical properties. N-acyl β3 peptides, where all residues are unnatural amino acids, are able to form helical fibrous structures by a head-to-tail assembly of helical monomers, extending the helix via a three point supramolecular hydrogen bonding motif. These helical nanorods were shown to be stable under a wide range of physical conditions, offering a self-assembled analogue of polymeric fibres. Hitherto the self-assembly has only been demonstrated between identical monomers; however the self-assembly motif is sequence-independent, offering the possibility of hetero-assembly of different peptide monomers. Here we present a proof of principle study of head-to-tail co-assembly of two different helical unnatural peptides Ac-β3[WELWEL] and Ac-β3[LIA], where the letters denote the β3 analogues of natural amino acids. By atomic force microscopy imaging it was demonstrated that the homo-assembly and co-assembly of these peptides yield characteristically different structures. Synchrotron small angle X-ray scattering experiments have confirmed the presence of the fibres in the solution and the averaged diameters from modelled data correlate well to the results of AFM imaging. Hence, there is evidence of co-assembly of the fibrous superstructures; given that different monomers may be used to introduce variations into chemical and physical properties, the results demonstrate a self-assembled analogue of a statistical co-polymer that can be used in designing complex functional nanomaterials.

scholarly journals Energy landscapes and dynamics of glycine on Cu(110)

2017 ◽  
Vol 19 (25) ◽  
pp. 16600-16605 ◽  
Author(s):  
Marco Sacchi ◽  
David J. Wales ◽  
Stephen J. Jenkins
Keyword(s):  
Amino Acids ◽  
Single Crystal ◽  
Long Range ◽  
Self Assembly ◽  
Metal Surfaces ◽  
The Self ◽  
Self Assembled Monolayers ◽  
Energy Landscapes ◽  
Assembly Mechanism ◽  
Assembled Monolayers

Amino acids adsorbed on single-crystal metal surfaces have emerged as prototypical systems for exploring the properties that govern the development of long-range chirality in self-assembled monolayers and supramolecular 2D networks. In this study, we characterise the self-assembly mechanism for glycine on the Cu(110) surface.

scholarly journals Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

2014 ◽  
Vol 10 ◽  
pp. 432-441 ◽  
Author(s):  
Rainer Hovorka ◽  
Sophie Hytteballe ◽  
Torsten Piehler ◽  
Georg Meyer-Eppler ◽  
Filip Topić ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Self Assembly ◽  
The Self ◽  
Assembly Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pyridine Ligands ◽  
Racemic Form

Two new 9,9’-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd]2+ and [(dppp)Pt]2+ ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and mass spectrometry. The racemic homochiral assemblies could also be characterised by single crystal X-ray diffraction.

Single-Crystal-like Materials by the Self-Assembly of Cube-Shaped Lead Zirconate Titanate (PZT) Microcrystals

Langmuir ◽  
2005 ◽  
Vol 21 (8) ◽  
pp. 3207-3212 ◽  
Author(s):  
Xiangyuan Liu ◽  
Elizabeth F. McCandlish ◽  
Larry E. McCandlish ◽  
Kate Mikulka-Bolen ◽  
Ramamoorthy Ramesh ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lead Zirconate Titanate ◽  
Self Assembly ◽  
Lead Zirconate ◽  
The Self ◽  
Zirconate Titanate

Unraveling the Self-Assembly Modes in Multicomponent Supramolecular Gels Using Single-Crystal X-ray Diffraction

2020 ◽  
Vol 32 (8) ◽  
pp. 3517-3527 ◽  
Author(s):  
Dipankar Ghosh ◽  
Abbas D. Farahani ◽  
Adam D. Martin ◽  
Pall Thordarson ◽  
Krishna K. Damodaran
Keyword(s):  
Single Crystal ◽  
Self Assembly ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
Supramolecular Gels

Calcium ion-assisted lipid tubule formation

2018 ◽  
Vol 2 (3) ◽  
pp. 603-608 ◽  
Author(s):  
Sandra Jones ◽  
An Huynh ◽  
Yuan Gao ◽  
Yan Yu
Keyword(s):  
Calcium Ions ◽  
Self Assembly ◽  
Calcium Ion ◽  
The Self ◽  
Tubule Formation

Calcium ions at mM concentrations promote the self-assembly of SOPC lipids into inter-connected hollow lipid tubes.

The Nature of Rapidly Extracted Phycocyanin from the Blue-Green Alga Plectonema Boryanum

1971 ◽  
Vol 29 ◽  
pp. 366-367
Author(s):  
M. Kessel ◽  
R. MacColl
Keyword(s):  
Self Assembly ◽  
Analytical Ultracentrifugation ◽  
Uranyl Acetate ◽  
The Self ◽  
Major Protein ◽  
Subunit Structure ◽  
Blue Green Alga ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Cacodylate Buffer

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.

Interrelationship of the cellular distribution and secretion of regular structure (RS) protein in Bacillus licheniformis nm 105

1992 ◽  
Vol 50 (1) ◽  
pp. 712-713
Author(s):  
Xiaorong Zhu ◽  
Richard McVeigh ◽  
Bijan K. Ghosh
Keyword(s):  
Alkaline Phosphatase ◽  
Bacillus Licheniformis ◽  
Self Assembly ◽  
Gel Electrophoresis ◽  
Culture Supernatant ◽  
Regular Structure ◽  
The Self ◽  
Cellular Distribution ◽  
Structural Protein ◽  
Laboratory Cultures

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.

Sign in / Sign up

Export Citation Format

Share Document