Tag: 高速AFMプローブ

Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation

The Endosomal Sorting Complex Required for Transport-III (ESCRT-III) is part of a conserved membrane remodeling machine. ESCRT-III employs polymer formation to catalyze inside-out membrane fission processes in a large variety of cellular processes, including budding of endosomal vesicles and enveloped viruses, cytokinesis, nuclear envelope reformation, plasma membrane repair, exosome formation, neuron pruning, dendritic spine maintenance, and preperoxisomal vesicle biogenesis.*

How membrane shape influences ESCRT-III polymerization and how ESCRT-III shapes membranes is yet unclear.*

In the article “Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation” Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau describe how human core ESCRT-III proteins, CHMP4B, CHMP2A, CHMP2B and CHMP3 are used to address this issue in vitro by combining membrane nanotube pulling experiments, cryo-electron tomography and Atomic Force Microscopy.*

The authors show that CHMP4B filaments preferentially bind to flat membranes or to tubes with positive mean curvature.*

The results presented in the article cited above underline the versatile membrane remodeling activity of ESCRT-III that may be a general feature required for cellular membrane remodeling processes.*

The authors provide novel insight on how mechanics and geometry of the membrane and of ESCRT-III assemblies can generate forces to shape a membrane neck.*

NanoWorld Ultra-Short AFM Cantilevers USC-F1.2-k0.15 were used for the High-speed Atomic Force Microscopy ( HS-AFM ) experiments presented in this article.*

Figure 1 from «Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation” by Aurélie Bertin et al.: CHMP4-ΔC flattens LUVs and binds preferentially to flat membranes or to membranes with a positive mean curvature. 1a CHMP4B-ΔC spirals observed by HS-AFM on a lipid bilayer. Scale bar: 50 nm. Please refer to the full article for the complete figure: https://rdcu.be/b5rOe
Figure 1 from «Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation” by Aurélie Bertin et al.:
CHMP4-ΔC flattens LUVs and binds preferentially to flat membranes or to membranes with a positive mean curvature.
1a CHMP4B-ΔC spirals observed by HS-AFM on a lipid bilayer. Scale bar: 50 nm.
Please refer to the full article for the complete figure: https://rdcu.be/b5rOe

*Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau
Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation
Nature Communications volume 11, Article number: 2663 (2020)
DOI: https://doi.org/10.1038/s41467-020-16368-5

Please follow this external link to read the full article: https://rdcu.be/b5rOe

Open Access The article “ Human ESCRT-III polymers assemble on positively curved membranes and induce helical membrane tube formation “ by Aurélie Bertin, Nicola de Franceschi, Eugenio de la Mora, Sourav Maity, Maryam Alqabandi, Nolwen Miguet, Aurélie di Cicco, Wouter H. Roos, Stéphanie Mangenot, Winfried Weissenhorn and Patricia Bassereau is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Cryopreservation of DNA Origami Nanostructures

Although DNA origami nanostructures have found their way into numerous fields of fundamental and applied research, they often suffer from rather limited stability when subjected to environments that differ from the employed assembly conditions, that is, suspended in Mg2+-containing buffer at moderate temperatures.*

In the article “Cryopreservation of DNA Origami Nanostructures” Yang Xin, Charlotte Kielar, Siqi Zhu, Christoph Sikeler, Xiaodan Xu, Christin Möser, Guido Grundmeier, Tim Liedl, Amelie Heuer-Jungemann, David M. Smith and Adrian Keller investigate means for efficient cryopreservation of 2D and 3D DNA origami nanostructures and, in particular, the effect of repeated freezing and thawing. It is found that, while the 2D DNA origami nanostructures maintain their structural integrity over at least 32 freeze–thaw cycles, ice crystal formation makes the DNA origami gradually more sensitive toward harsh sample treatment conditions. *

The cryoprotectants glycerol and trehalose are found to efficiently protect the DNA origami nanostructures against freeze damage at concentrations between 0.2 × 10−3and 200 × 10−3m and without any negative effects on DNA origami shape. This work thus provides a basis for the long-term storage of DNA origami nanostructures, which is an important prerequisite for various technological and medical applications. *

NanoWorld Ultra-Short Cantilevers for High-Speed AFM USC-F0.3-k0.3 were used for the AFM imaging in liquid of the DNA  origami sample described in this article.

Figure 2 from “Cryopreservation of DNA Origami Nanostructures” by Yang Xin et al.: AFM images of triangular DNA origami nanostructures after 32 freeze–thaw cycles measured a) in air and b) in liquid. AFM images of triangular DNA origami nanostructures assembled from scaffold and staple strands that were subjected to 32 freeze–thaw cycles measured c) in air and d) in liquid. Images have a size of 1.5 × 1.5 μm2 and height scales are 2.3 nm.
Figure 2 from “Cryopreservation of DNA Origami Nanostructures” by Yang Xin et al.:

AFM images of triangular DNA origami nanostructures after 32 freeze–thaw cycles measured a) in air and b) in liquid. AFM images of triangular DNA origami nanostructures assembled from scaffold and staple strands that were subjected to 32 freeze–thaw cycles measured c) in air and d) in liquid. Images have a size of 1.5 × 1.5 μm2 and height scales are 2.3 nm.

*Yang Xin, Charlotte Kielar, Siqi Zhu, Christoph Sikeler, Xiaodan Xu, Christin Möser, Guido Grundmeier, Tim Liedl, Amelie Heuer-Jungemann, David M. Smith and Adrian Keller
Cryopreservation of DNA Origami Nanostructures
Small 2020, 16, 1905959
DOI: 10.1002/smll.20190595

Please follow this external link to read the full article: https://onlinelibrary.wiley.com/doi/pdf/10.1002/smll.201905959

Open Access The article “ Cryopreservation of DNA Origami Nanostructures “ by Yang Xin, Charlotte Kielar, Siqi Zhu, Christoph Sikeler, Xiaodan Xu, Christin Möser, Guido Grundmeier, Tim Liedl, Amelie Heuer-Jungemann, David M. Smith and Adrian Keller is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Self-assembly of small molecules at hydrophobic interfaces using group effect

Although common in nature, the self-assembly of small molecules at sold–liquid interfaces is difficult to control in artificial systems. The high mobility of dissolved small molecules limits their residence at the interface, typically restricting the self-assembly to systems under confinement or with mobile tethers between the molecules and the surface. Small hydrogen-bonding molecules can overcome these issues by exploiting group-effect stabilization to achieve non-tethered self-assembly at hydrophobic interfaces. Significantly, the weak molecular interactions with the solid makes it possible to influence the interfacial hydrogen bond network, potentially creating a wide variety of supramolecular structures.*

In the paper “Self-assembly of small molecules at hydrophobic interfaces using group effect” William Foster, Keisuke Miyazawa, Takeshi Fukuma, Halim Kusumaatmaja and Kislon Voϊtchovsky investigate the nanoscale details of water and alcohols mixtures self-assembling at the interface with graphite through group-effect. They explore the interplay between inter-molecular and surface interactions by adding small amounts of foreign molecules able to interfere with the hydrogen bond network and systematically varying the length of the alcohol hydrocarbon chain. The resulting supramolecular structures forming at room temperature are then examined using atomic force microscopy with insights from computer simulations.*

The authors show that the group-based self-assembly approach investigated in the paper is general and can be reproduced on other substrates such as molybdenum disulphide and graphene oxide, potentially making it relevant for a wide variety of systems.*

NanoWorld Arrow UHF-AuD ultra high frequency cantilevers for High Speed AFM were used for the amplitude modulation atomic force microscopy described in this paper.


Figure 4 from “Self-assembly of small molecules at hydrophobic interfaces using group effect“ by William Foster et al.:
Impact of the backbone length of primary alcohols on interfacial self-assembly on HOPG. The basic monolayer motif is visible as expected in a 50 : 50 methanol : water mixture (a), here imaged by amplitude-modulation AFM (topography image). In a 50 : 50 ethanol : water mixture (b), two organised layers are visible both in topography and in the phase where it is more pronounced, outlined by a white dashed line (blue and red arrows). In phase, the self-assembled layers appear darker than the directly exposed graphite, where no structures are present (black arrow). The lower layer shows few resolvable features and is bordered by wide rows that have a separation of 5.89 ± 0.28 nm. In 50 : 50 1-propanol : water mixture (c), novel structures with long, straight edges emerge (red arrow) and grow on top of the exposed graphite (black arrow). The structures have a row periodicity of 5.86 ± 0.25 nm. The inset shows details of the longitudinal row structures near an edge. Further variance is seen in a 50 : 50 2-propanol : water mixture (d) where two types of domains form (red and blue arrows), both demonstrating a clear phase contrast with the graphite surface (black arrow). The domains have longitudinal rows with periodicities of 6.10 ± 0.35 nm (blue arrow) and 4.91 ± 0.45 nm (red arrow). Unlike for (c), higher resolution of the row (inset) evidence curved edges. The scale bars are 50 nm in (a) and (b), 100 nm in (c) and (d) main image and 20 nm in the insets. The purple colour scale bar represents a height variation of 1 nm in (a), (b) and (d), 3 nm in (c) and 0.5 nm in the insets. The blue scale bar represents a phase variation of 1.5° in (b), 2° in (c) and its inset and 15° in (d) and its inset.

*William Foster, Keisuke Miyazawa, Takeshi Fukuma, Halim Kusumaatmaja and Kislon Voϊtchovsky
Self-assembly of small molecules at hydrophobic interfaces using group effect
Nanoscale, 2020,12, 5452
DOI: 10.1039/c9nr09505e

Please follow this external link to read the full article: https://pubs.rsc.org/en/content/articlepdf/2020/nr/c9nr09505e

Open Access: The paper « Self-assembly of small molecules at hydrophobic interfaces using group effect»  by William Foster, Keisuke Miyazawa, Takeshi Fukuma, Halim Kusumaatmaja and Kislon Voϊtchovsky is licensed under a Creative Commons Attribution 3.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/3.0/.