Towards three-dimensional structural determination of amorphous materials at atomic resolution

2013 ◽  
Vol 88 (10) ◽  
Author(s):  
Chun Zhu ◽  
Chien-Chun Chen ◽  
Jincheng Du ◽  
Michael R. Sawaya ◽  
M. C. Scott ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Three Dimensional ◽  
Atomic Resolution ◽  
Structural Determination

Progress on the Three-Dimensional Structural Determination of Trypsin-Modified EF-TU-GDP

1989 ◽  
pp. 15-25 ◽  
Author(s):  
Frances Jurnak ◽  
Michelle Nelson ◽  
Marilyn Yoder ◽  
Susan Heffron ◽  
Suet Miu
Keyword(s):  
Three Dimensional ◽  
Structural Determination

Electron Crystallographic Determination of the Structure of Bacteriorhodopsin

1990 ◽  
Vol 48 (1) ◽  
pp. 90-91
Author(s):  
R. Henderson ◽  
J.M. Baldwin ◽  
T.A. Ceska ◽  
E. Beckman ◽  
F. Zemlin ◽  
...  
Keyword(s):  
High Resolution ◽  
Proton Pump ◽  
Three Dimensional ◽  
Atomic Resolution ◽  
Two Dimensional ◽  
New Methods ◽  
Density Map ◽  
Diffraction Patterns

The light driven proton pump bacteriorhodopsin (bR) occurs naturally as two-dimensional crystals. A three-dimensional density map of the structure, at near atomic resolution, has been obtained by studying the crystals using electron cryo-microscopy to obtain diffraction patterns and high resolution micrographs (1).New methods have been developed for analysing micrographs from tilted specimens, incorporating the methods previously developed for untilted specimens that enable large areas to be analysed and corrected for distortions. Data from 72 images, from both tilted and untilted specimens, have been analysed to produce the phases of 2700 independent Fourier components of the structure. The amplitudes of these components have been accurately measured from 150 diffraction patterns. Together, these data represent about half of the full three-dimensional transform to 3.5 Å. The distribution of the data which is included in the map is shown in fig. 1. For specimen tilts up to around 20° the data is essentially complete. For higher tilts the data is more sparsely sampled, and is at present about half complete.

scholarly journals Three-dimensional electron diffraction for porous crystalline materials: structural determination and beyond

2021 ◽  
Author(s):  
Zhehao Huang ◽  
Tom Willhammar ◽  
Xiaodong Zou
Keyword(s):  
Electron Diffraction ◽  
Three Dimensional ◽  
Structural Determination ◽  
New Materials ◽  
Dimensional Electron ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Details

Three-dimensional electron diffraction is a powerful tool for accurate structure determination of zeolite, MOF, and COF crystals that are too small for X-ray diffraction. By revealing the structural details, the properties of the materials can be understood, and new materials and applications can be designed.

scholarly journals Double-Helix Supramolecular Nanofibers Assembled from Negatively Curved Nanographenes

2020 ◽  
Author(s):  
Kenta Kato ◽  
Kiyofumi Takaba ◽  
Saori Maki-Yonekura ◽  
Nobuhiko Mitoma ◽  
Yusuke Nakanishi ◽  
...  
Keyword(s):  
Self Assembly ◽  
Negative Curvature ◽  
Double Helix ◽  
Three Dimensional ◽  
Structural Determination ◽  
Dimensional Electron ◽  
Electron Crystallography ◽  
One Dimensional ◽  
Negatively Curved

The layered structures of graphite and related nanographene molecules play key roles in their physical and electronic functions. However, the stacking modes of negatively curved nanographenes remains unclear, owing to the lack of suitable nanographene molecules. Herein we report the synthesis and one-dimensional supramolecular self-assembly of negatively curved nanographenes without any assembly-assisting substituents. This curved nanographene self-assembles in various organic solvents and acts as an efficient gelator. The formation of nanofibers was confirmed by microscopic measurements, and an unprecedented double-helix assembly by continuous π-π stacking was uncovered by three-dimensional electron crystallography. This work not only reports the discovery of an all-sp<sup>2</sup>-carbon supramolecular π-organogelator with negative curvature, but also demonstrates the power of three-dimensional electron crystallography for the structural determination of submicrometer-sized molecular alignment.

Instrumentation and methodology for electron crystallography

1991 ◽  
Vol 49 ◽  
pp. 420-421
Author(s):  
Kenneth H. Downing
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Three Dimensional ◽  
Atomic Resolution ◽  
Single Atom ◽  
Electron Crystallography ◽  
Density Map ◽  
Low Exposure ◽  
Under Construction

The determination of three-dimensional structures of macromolecules at atomic resolution remains one oμf the great promises of electron microscopy. Instrumental problems which had to be overcome in order to achieve single-atom resolution have long been recognized and to a large extent overcome. It is interesting to note that most of the instrumental developments were already incorporated in a microscope under construction over 20 years ago. However, the application of techniques to circumvent limitations imposed by the sensitivity of organic specimen to radiation damage are still developing. Electron crystallography, which takes advantage of the ability to obtain useful information from images taken at very low exposure, is close to realizing the potential. The state of electron crystallography has advanced rapidly during the last few years. The structure of one protein, bacteriorhodopsin, has been determined from EM data, and several other structures are advanced to the point of fitting the peptide chain to a high-resolution density map.

scholarly journals Double-Helix Supramolecular Nanofibers Assembled from Negatively Curved Nanographenes

2020 ◽  
Author(s):  
Kenta Kato ◽  
Kiyofumi Takaba ◽  
Saori Maki-Yonekura ◽  
Nobuhiko Mitoma ◽  
Yusuke Nakanishi ◽  
...  
Keyword(s):  
Self Assembly ◽  
Negative Curvature ◽  
Double Helix ◽  
Three Dimensional ◽  
Structural Determination ◽  
Dimensional Electron ◽  
Electron Crystallography ◽  
One Dimensional ◽  
Negatively Curved

The layered structures of graphite and related nanographene molecules play key roles in their physical and electronic functions. However, the stacking modes of negatively curved nanographenes remains unclear, owing to the lack of suitable nanographene molecules. Herein we report the synthesis and one-dimensional supramolecular self-assembly of negatively curved nanographenes without any assembly-assisting substituents. This curved nanographene self-assembles in various organic solvents and acts as an efficient gelator. The formation of nanofibers was confirmed by microscopic measurements, and an unprecedented double-helix assembly by continuous π-π stacking was uncovered by three-dimensional electron crystallography. This work not only reports the discovery of an all-sp<sup>2</sup>-carbon supramolecular π-organogelator with negative curvature, but also demonstrates the power of three-dimensional electron crystallography for the structural determination of submicrometer-sized molecular alignment.

NMR of Larger Proteins: Approach to the Structural Analyses of Antibody

1997 ◽  
Author(s):  
Yoji Arata
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Isotope Labeling ◽  
Relaxation Times ◽  
Three Dimensional ◽  
Atomic Resolution ◽  
Dimensional Structure ◽  
High Resolution Nmr ◽  
Structure Of Proteins

The first 1H NMR spectrum of a protein, bovine pancreatic ribonuclease, reported in 1957 by Saunders et al. was accounted for by Jardetzky and Jardetzky (1957) in terms of the spectra of the constituent ammo acids. Jardetzky and coworkers continued to report a series of important papers describing the potential usefulness of high-resolution NMR (Roberts and Jardetzky, 1970). Modern NMR of proteins began with the classic paper published in 1968 by Markley, Putter, and Jardetzky, who beautifully demonstrated the possibility of using stable-isotope labeling for the structural analyses of proteins in solution (Markley et al., 1968). Five years before the publication of this paper, Jardetzky gave an important lecture in Tokyo, stressing the importance of NMR particularly in combination with deuterium labeling as a potential solution version of X-ray crystallography for the determination of the three-dimensional structure of proteins (Jardetzky, 1965). The impact of Jardetzky’s contribution was great, eventually leading to the now well-established combination of multidimensional NMR and stable-isotope labeling for the determination of the three-dimensional structure of proteins in solution. High-resolution NMR of biological macromolecules takes advantage of the fact that 1H, 13C, and 15N, all of which are spin 1/2 nuclei, possess long relaxation times, which primarily are due to weak dipole-dipole interactions. Thus, phase memory can be retained long enough to extract relevant information on the spin system by fully making use of multidimensional techniques. This makes high-resolution NMR special as a tool for structural analyses at atomic resolution. By contrast, relaxation times are far shorter in the case of visible, ultraviolet, infrared, and Raman spectroscopy, where much stronger interactions are involved. For this reason no structural analyses at atomic resolution are possible using these types of spectroscopy. However, an increase in the molecular weight eventually creates difficulties in achieving sufficient spectral resolution to be able to separate and assign each of the resonances of a protein. This is due to 1) a limitation of the strength of static magnetic field available and more importantly 2) an unavoidable shortening of relaxation times originating from the slow tumbling motion of the protein molecules in solution.

Sign in / Sign up

Export Citation Format

Share Document