scholarly journals Synergistic role of nucleotides and lipids for the self-assembly of Shs1 septin oligomers

2020 ◽  
Vol 477 (14) ◽  
pp. 2697-2714
Author(s):  
Cyntia Taveneau ◽  
Rémi Blanc ◽  
Gérard Péhau-Arnaudet ◽  
Aurélie Di Cicco ◽  
Aurélie Bertin
Keyword(s):  
Self Assembly ◽  
Structural Organization ◽  
Electron Tomography ◽  
Budding Yeast ◽  
The Self ◽  
Two Dimensional ◽  
Molecular Polymorphism ◽  
Cryo Electron Tomography ◽  
First Time

Budding yeast septins are essential for cell division and polarity. Septins assemble as palindromic linear octameric complexes. The function and ultra-structural organization of septins are finely governed by their molecular polymorphism. In particular, in budding yeast, the end subunit can stand either as Shs1 or Cdc11. We have dissected, here, for the first time, the behavior of the Shs1 protomer bound to membranes at nanometer resolution, in complex with the other septins. Using electron microscopy, we have shown that on membranes, Shs1 protomers self-assemble into rings, bundles, filaments or two-dimensional gauzes. Using a set of specific mutants we have demonstrated a synergistic role of both nucleotides and lipids for the organization and oligomerization of budding yeast septins. Besides, cryo-electron tomography assays show that vesicles are deformed by the interaction between Shs1 oligomers and lipids. The Shs1–Shs1 interface is stabilized by the presence of phosphoinositides, allowing the visualization of micrometric long filaments formed by Shs1 protomers. In addition, molecular modeling experiments have revealed a potential molecular mechanism regarding the selectivity of septin subunits for phosphoinositide lipids.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

scholarly journals Understanding the role of conjugation length on the self-assembly behaviour of oligophenyleneethynylenes

2021 ◽  
Author(s):  
Beatriz Matarranz ◽  
Goutam Ghosh ◽  
Ramesh Kandanelli ◽  
Angel Sampedro ◽  
Kalathil K. Kartha ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Conjugation Length ◽  
The Relationship

We unravel the relationship between conjugation length and self-assembly behaviour of oligophenyleneethynylenes (OPEs).

scholarly journals Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

Role of Multivalent Cations in the Self-Assembly of Phospholipid−DNA Complexes

2007 ◽  
Vol 111 (51) ◽  
pp. 14233-14238 ◽  
Author(s):  
Guillaume Tresset ◽  
Wun Chet Davy Cheong ◽  
Yeng Ming Lam
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Dna Complexes

A dissipative particle dynamics simulation study on phase diagrams for the self-assembly of amphiphilic hyperbranched multiarm copolymers in various solvents

Soft Matter ◽  
2017 ◽  
Vol 13 (36) ◽  
pp. 6178-6188 ◽  
Author(s):  
Haina Tan ◽  
Chunyang Yu ◽  
Zhongyuan Lu ◽  
Yongfeng Zhou ◽  
Deyue Yan
Keyword(s):  
Phase Diagrams ◽  
Simulation Study ◽  
Self Assembly ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
The Self ◽  
Dynamics Simulation ◽  
Dynamics Simulations ◽  
First Time ◽  
Dissipative Particle Dynamics Simulation

This work discloses for the first time the self-assembly phase diagrams of amphiphilic hyperbranched multiarm copolymers in various solvents by dissipative particle dynamics simulations.

Self-Assembly of Alkali Lignin in Tetrahydrofuran

2012 ◽  
Vol 550-553 ◽  
pp. 57-61
Author(s):  
Hao Li ◽  
Yong Hong Deng ◽  
Kai Huang
Keyword(s):  
Charge Transfer ◽  
Electrostatic Interaction ◽  
Self Assembly ◽  
The Self ◽  
Charge Transfer Complexes ◽  
Layer By Layer ◽  
Alkali Lignin ◽  
Higher Temperature ◽  
Effects Of Temperature

Alkali lignin (AL) was used as a polyanion to form layer-by-layer self-assembled film with PDAC as a polycation. The effects of temperature and concentration on the adsorption characteristics of AL were investigated. Iodine was added into AL solutions to study the role of π-π interaction in self-assembly of AL and PDAC. Results show that the self-assembly of AL/PDAC is mainly driven by π-π interaction and electrostatic interaction. A higher temperature or a larger concentration can enhance the aggregation of lignin. I2 can form lignin–iodine charge–transfer complexes with AL to reduce the degree of aggregation of AL, so the adsorbed amount of AL decreases significantly with increasing iodine contents.

On the Role of Chirality in Guiding the Self-Assembly of Peptides

2017 ◽  
Vol 129 (43) ◽  
pp. 13473-13477 ◽  
Author(s):  
Shibaji Basak ◽  
Ishwar Singh ◽  
Annaleizle Ferranco ◽  
Jebreil Syed ◽  
Heinz-Bernhard Kraatz
Keyword(s):  
Self Assembly ◽  
The Self

Two-dimensional FeS2-encapsulated Au: a quasi-epitaxial heterojunction for synergistic catalytic activity under photoelectrocatalytic water reduction

2019 ◽  
Vol 7 (33) ◽  
pp. 19258-19268 ◽  
Author(s):  
Indranil Mondal ◽  
Song Yi Moon ◽  
Hyunhwa Lee ◽  
Heeyoung Kim ◽  
Jeong Young Park
Keyword(s):  
Electron Transfer ◽  
Catalytic Activity ◽  
Structural Organization ◽  
Two Dimensional ◽  
Hot Electron ◽  
Water Reduction ◽  
Hot Electron Transfer

Optimization of structural organization between metal and semiconductor electrocatalyst reveals the hot role of quasi-epitaxial heterojunction in hot electron transfer for synergistic photocatalysis.

A self-assembly based on a hydrogel interface: facile, rapid, and large-scale preparation of colloidal photonic crystals

2020 ◽  
Vol 4 (8) ◽  
pp. 2409-2417
Author(s):  
Mengfan Wu ◽  
Chuyan Zhang ◽  
Fujing Wei ◽  
Huifang An ◽  
Xiaqing Wang ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Self Assembly ◽  
Large Scale ◽  
The Self ◽  
Colloidal Photonic Crystals ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
First Time

This is the first time that a hydrogel interface has been used as an assembly interface for the self-assembly of photonic crystals with excellent performances.

scholarly journals PACRG and FAP20 form the inner junction of axonemal doublet microtubules and regulate ciliary motility

2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1816 ◽  
Author(s):  
Erin E. Dymek ◽  
Jianfeng Lin ◽  
Gang Fu ◽  
Mary E. Porter ◽  
Daniela Nicastro ◽  
...  
Keyword(s):  
Cell Motility ◽  
Electron Tomography ◽  
Structural Studies ◽  
Ciliary Beating ◽  
Ciliary Motility ◽  
Functional Studies ◽  
Cryo Electron Tomography ◽  
Motile Cilia

We previously demonstrated that PACRG plays a role in regulating dynein-driven microtubule sliding in motile cilia. To expand our understanding of the role of PACRG in ciliary assembly and motility, we used a combination of functional and structural studies, including newly identified Chlamydomonas pacrg mutants. Using cryo-electron tomography we show that PACRG and FAP20 form the inner junction between the A- and B-tubule along the length of all nine ciliary doublet microtubules. The lack of PACRG and FAP20 also results in reduced assembly of inner-arm dynein IDA b and the beak-MIP structures. In addition, our functional studies reveal that loss of PACRG and/or FAP20 causes severe cell motility defects and reduced in vitro microtubule sliding velocities. Interestingly, the addition of exogenous PACRG and/or FAP20 protein to isolated mutant axonemes restores microtubule sliding velocities, but not ciliary beating. Taken together, these studies show that PACRG and FAP20 comprise the inner junction bridge that serves as a hub for both directly modulating dynein-driven microtubule sliding, as well as for the assembly of additional ciliary components that play essential roles in generating coordinated ciliary beating.

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