Imaging of reconstituted biological channels at molecular resolution by atomic force microscopy

1993 ◽  
Vol 265 (3) ◽  
pp. C851-C856 ◽  
Author(s):  
R. Lal ◽  
H. Kim ◽  
R. M. Garavito ◽  
M. F. Arnsdorf
Keyword(s):  
Atomic Force Microscopy ◽  
High Resolution ◽  
Internal Control ◽  
Imaging Method ◽  
Buffer Solution ◽  
Electron Microscopic ◽  
Ompf Porin ◽  
Force Microscopy ◽  
Atomic Force ◽  
Rectangular Pattern

Using atomic force microscopy (AFM), we obtained high-resolution surface images of the bacterial outer membrane channels Escherichia coli OmpF porin and Bordetella pertussis porin that were reconstituted in artificial bilayer membranes as two-dimensional crystalline arrays. These porins were chosen because they are among the most extensively studied proteins of this type and are known for their well-defined crystalline nature in the native membrane. Such reconstituted membrane proteins are ideal specimens to assess the suitability and resolution of AFM for imaging biomembranes and associated proteins. Although OmpF porin often showed a mixed pattern of rectangular and hexagonal arrays with approximately 8.4 x 9.8- and approximately 7.2-nm-spacings, respectively, B. pertussis porin showed mostly a rectangular pattern with an approximately 7.9 x 13.8-nm spacing. The packing patterns of the E. coli OmpF porin in the membrane are very close to those found in electron-microscopic studies. When B. pertussis porin was imaged in a buffer solution, its trimeric subunits were apparently resolved, and the surface of each monomer revealed beadlike structures. This is the first report of such a high-resolution structural analysis of B. pertussis porin by any imaging method. We also imaged the lipid bilayer itself as an internal control for imaging and to further ascertain the resolution. Individual polar head groups of bilayer lipid molecules were resolved, suggesting the intrinsic resolution of AFM for bioimaging.

scholarly journals Exploring Intramolecular Methyl–Methyl Coupling on a Metal Surface for Edge-Extended Graphene Nanoribbons

2021 ◽  
Vol 03 (02) ◽  
pp. 128-133
Author(s):  
Zijie Qiu ◽  
Qiang Sun ◽  
Shiyong Wang ◽  
Gabriela Borin Barin ◽  
Bastian Dumslaff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Atomic Force Microscopy ◽  
High Resolution ◽  
Graphene Nanoribbons ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Methyl Methyl ◽  
Atomic Force ◽  
Edge Extension

Intramolecular methyl–methyl coupling on Au (111) is explored as a new on-surface protocol for edge extension in graphene nanoribbons (GNRs). Characterized by high-resolution scanning tunneling microscopy, noncontact atomic force microscopy, and Raman spectroscopy, the methyl–methyl coupling is proven to indeed proceed at the armchair edges of the GNRs, forming six-membered rings with sp3- or sp2-hybridized carbons.

scholarly journals Dialysis Purification of Integrase-DNA Complexes Provides High-Resolution Atomic Force Microscopy Images: Dimeric Recombinant HIV-1 Integrase Binding and Specific Looping on DNA

PLoS ONE ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. e53572 ◽  
Author(s):  
Tatsuaki Tsuruyama ◽  
Tonau Nakai ◽  
Rei Ohmori ◽  
Munetaka Ozeki ◽  
Keiji Tamaki ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Resolution ◽  
Dna Complexes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Hiv 1

Imaging of Xenopus laevis Oocyte Plasma Membrane in Physiological-Like Conditions by Atomic Force Microscopy

2013 ◽  
Vol 19 (5) ◽  
pp. 1358-1363 ◽  
Author(s):  
Massimo Santacroce ◽  
Federica Daniele ◽  
Andrea Cremona ◽  
Diletta Scaccabarozzi ◽  
Michela Castagna ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Plasma Membrane ◽  
High Resolution ◽  
Membrane Proteins ◽  
Xenopus Laevis ◽  
Functional Study ◽  
Xenopus Laevis Oocyte ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

AbstractXenopus laevis oocytes are an interesting model for the study of many developmental mechanisms because of their dimensions and the ease with which they can be manipulated. In addition, they are widely employed systems for the expression and functional study of heterologous proteins, which can be expressed with high efficiency on their plasma membrane. Here we applied atomic force microscopy (AFM) to the study of the plasma membrane of X. laevis oocytes. In particular, we developed and optimized a new sample preparation protocol, based on the purification of plasma membranes by ultracentrifugation on a sucrose gradient, to perform a high-resolution AFM imaging of X. laevis oocyte plasma membrane in physiological-like conditions. Reproducible AFM topographs allowed visualization and dimensional characterization of membrane patches, whose height corresponds to a single lipid bilayer, as well as the presence of nanometer structures embedded in the plasma membrane and identified as native membrane proteins. The described method appears to be an applicable tool for performing high-resolution AFM imaging of X. laevis oocyte plasma membrane in a physiological-like environment, thus opening promising perspectives for studying in situ cloned membrane proteins of relevant biomedical/pharmacological interest expressed in this biological system.

Investigation of surface morphology of thin metal films with magnetic layers Fe-Cr-Co

2021 ◽  
Author(s):  
V.S. Zayonchkovsky ◽  
Aung Kyaw Kyaw ◽  
A.V. Andreev
Keyword(s):  
Atomic Force Microscopy ◽  
Magnetron Sputtering ◽  
Electron Microscopic Examination ◽  
Nearest Neighbors ◽  
Substrate Plane ◽  
Large Area ◽  
Electron Microscopic ◽  
Force Microscopy ◽  
Atomic Force ◽  
Large Projection

Films containing layers of dispersion-hardening alloys (LDHA) based on the Fe-Cr-Co system were obtained by magnetron sputtering. LDHA acquire the properties of film permanent magnets after a single-stage «fast» high-vacuum annealing. Bulk materials acquire such properties only after many hours of multi-stage heat treatment. The film samples acquire these properties in tens of seconds. The morphology of their surface was studied to determine the origin of the coercive force of film samples. The surface morphology was studied using high resolution scanning electron microscopy and atomic force microscopy. We studied two compositions that, in bulk, have a different tendency to form many phases during crystallization. In magnetron sputtering, the alloy in which a multiphase state is easily formed is polycrystalline. The antipode alloy in magnetron sputtering is realized in an amorphous state. After annealing, both alloys are in a polycrystalline state. Electron microscopic examination showed that as a result of annealing, crystallites are formed with a large projection onto the substrate plane, which grow due to the nearest neighbors. Moreover, these crystallites have not only a large area, but also a height. After annealing, both alloys are in a polycrystalline state. Electron microscopic examination showed that as a result of annealing, crystallites are formed with a large projection onto the substrate plane, which grow due to the nearest neighbors. Moreover, these crystallites have not only a large area, but also a height. What is determined by atomic force microscopy. High crystallites are also faceted. This may indicate that the composition of these crystallites differs from the composition of the surrounding layer, which may be the reason for the increase in coercive force as a result of annealing.

High-resolution transmission electron microscopic investigations of molybdenum thin films on faceted α-Al2O3

2005 ◽  
Vol 38 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Leonore Wiehl ◽  
Jens Oster ◽  
Michael Huth
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Epitaxial Relationship ◽  
Electron Microscopic ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Α Al2o3 ◽  
Relationship Of

Epitaxially grown Mo films on a faceted corundum (α-Al2O3)mplane were investigated by transmission electron microscopy. Low- and high-resolution images were taken from a cross-section specimen cut perpendicular to the facets. It was possible to identify unambiguously the crystallographic orientation of these facets and explain the considerable deviation (∼10°) of the experimental interfacet angle, as measured with atomic force microscopy (AFM), from the expected value. For the first time, proof is given for a smooth \{10\bar{1}1\} facet and a curvy facet with orientation near to \{10\bar{1}\bar{2}\}. Moreover, the three-dimensional epitaxial relationship of an Mo film on a faceted corundummsurface was determined.

Diabetes increases stiffness of live cardiomyocytes measured by atomic force microscopy nanoindentation

2014 ◽  
Vol 307 (10) ◽  
pp. C910-C919 ◽  
Author(s):  
Juan C. Benech ◽  
Nicolás Benech ◽  
Ana I. Zambrana ◽  
Inés Rauschert ◽  
Verónica Bervejillo ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Physiological Condition ◽  
Diabetic Mice ◽  
Cell Nuclei ◽  
Buffer Solution ◽  
Isolated Cardiomyocytes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Myocardial Fibers

Stiffness of live cardiomyocytes isolated from control and diabetic mice was measured using the atomic force microscopy nanoindentation method. Type 1 diabetes was induced in mice by streptozotocin administration. Histological images of myocardium from mice that were diabetic for 3 mo showed disorderly lineup of myocardial cells, irregularly sized cell nuclei, and fragmented and disordered myocardial fibers with interstitial collagen accumulation. Phalloidin-stained cardiomyocytes isolated from diabetic mice showed altered (i.e., more irregular and diffuse) actin filament organization compared with cardiomyocytes from control mice. Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) pump expression was reduced in homogenates obtained from the left ventricle of diabetic animals compared with age-matched controls. The apparent elastic modulus (AEM) for live control or diabetic isolated cardiomyocytes was measured using the atomic force microscopy nanoindentation method in Tyrode buffer solution containing 1.8 mM Ca2+ and 5.4 mM KCl (physiological condition), 100 nM Ca2+ and 5.4 mM KCl (low extracellular Ca2+ condition), or 1.8 mM Ca2+ and 140 mM KCl (contraction condition). In the physiological condition, the mean AEM was 112% higher for live diabetic than control isolated cardiomyocytes (91 ± 14 vs. 43 ± 7 kPa). The AEM was also significantly higher in diabetic than control cardiomyocytes in the low extracellular Ca2+ and contraction conditions. These findings suggest that the material properties of live cardiomyocytes were affected by diabetes, resulting in stiffer cells, which very likely contribute to high diastolic LV stiffness, which has been observed in vivo in some diabetes mellitus patients.

High-Resolution Frequency-Modulation Atomic Force Microscopy in Liquids Using Electrostatic Excitation Method

2010 ◽  
Vol 3 (6) ◽  
pp. 065205 ◽  
Author(s):  
Ken-ichi Umeda ◽  
Noriaki Oyabu ◽  
Kei Kobayashi ◽  
Yoshiki Hirata ◽  
Kazumi Matsushige ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Resolution ◽  
Frequency Modulation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Excitation Method

High-resolution noncontact atomic force microscopy

2009 ◽  
Vol 20 (26) ◽  
pp. 260201-260201 ◽  
Author(s):  
Rubén Pérez ◽  
Ricardo García ◽  
Udo Schwarz
Keyword(s):  
Atomic Force Microscopy ◽  
High Resolution ◽  
Force Microscopy ◽  
Atomic Force
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