3-D diffraction intensities of the crotoxin complex crystal

1986 ◽  
Vol 44 ◽  
pp. 162-163
Author(s):  
B.V.V. Prasad ◽  
L.L. Degn ◽  
T.-W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Data Set ◽  
Crotalus Durissus Terrificus ◽  
Cold Stage ◽  
Resolution Electron ◽  
Diffraction Patterns ◽  
Crotalus Durissus ◽  
Complex Crystal

The crotoxin complex, a neurotoxin from the venom of the Brazilian rattlesnake, Crotalus durissus terrificus, forms thin crystals suitable for high resolution electron crystallography. These crystals grow to variable completions of the unit cell, making it difficult to merge the intensity data from different crystals. This difficulty is overcome by collecting as many electron diffraction patterns (EDP) as possible from a single crystal tilted from +60° to -60°. Several series of approximately twenty EDP's were collected using a Philips 400 equipped with a cold stage at MRC, Cambridge in Dr. R. Henderson's laboratory. We report here our progress in synthesizing a 3-D intensity data set from these series.

Imaging of the crotoxin crystal in vitreous ice at 3.9 Å resolution

1987 ◽  
Vol 45 ◽  
pp. 646-647
Author(s):  
L. L. Degn
Keyword(s):  
High Resolution ◽  
Crystallographic Analysis ◽  
Specimen Preparation ◽  
High Resolution Imaging ◽  
Technical Problems ◽  
Resolution Electron ◽  
Resolution Imaging ◽  
Diffraction Patterns ◽  
Crotalus Durissus ◽  
Complex Crystal

The crotoxin complex is a 24,500 dalton neurotoxic protein isolated from the venom of the Brazilian rattlesnake Crotalus durissus terrificus. The crotoxin complex crystallizes as thin crystals suitable for high resolution 3-D reconstruction by electron crystallographic analysis. High resolution imaging of an untilted crotoxin complex crystal embedded in glucose has been reported. Presented here is high resolution (3.9 Å) imaging of an untilted crotoxin complex crystal embedded in vitreous ice.Several technical problems are involved in the collection of high resolution electron crystallographic data for 3-D reconstruction. First, the specimen should be as flat as possible on the grid since bending due to specimen preparation or due to beam-induced movement may cause smeared reflections in electron diffraction patterns or optical diffractograms, a phenomenon that is particularly noticeable in highly tilted specimens.

Characteristic feature on structure analyzed by high-resolution electron crystallography

1995 ◽  
Vol 53 ◽  
pp. 834-835
Author(s):  
Y. Fujiyoshi ◽  
K. Mitsuoka ◽  
T. Hirai ◽  
K. Murata ◽  
A. Miyazawa ◽  
...  
Keyword(s):  
Amino Acid ◽  
High Resolution ◽  
Characteristic Feature ◽  
Proton Pump ◽  
Ccd Camera ◽  
Electron Crystallography ◽  
Embedding Technique ◽  
Resolution Electron ◽  
Ph Conditions ◽  
Diffraction Patterns

The structure of bacteriorhodopsin (bR), which was already analyzed by Henderson et al., is studied by our new electron cryo-microscope equipped with Field Emission Gun (FEG) and Slow Scan CCD camera (SSCCD), because our system together with ice embedding technique enable us to solve the structure of bR at various pH conditions between pH 4.0 and 10.0. Ionization of amino acid is naturally closely related to the translocation of proton and then the function of the proton pump of bR. Therefore, observation of translocation of proton in bR is very important, if possible. Both ice embedding and high resolution techniques are essential to achieve this intention. Therefore, we intended to develop an electron cryo-microscope fit to these techniques and recently we had succeeded it.We collected whole sets of diffraction patterns for bR up to 70 degree tilt at pH 5.5 by using SSCCD, and merged these data of 300 diffraction patterns.

Preparation of Frozen Hydrated Purple Membrane for High Resolution Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 72-73
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Structural Information ◽  
Carbon Film ◽  
High Resolution Electron Microscopy ◽  
Purple Membrane ◽  
Current Time ◽  
Cold Stage ◽  
Resolution Electron ◽  
Diffraction Patterns ◽  
Transfer Device

At the current time the only method that has led to high resolution structural information greater than 7 Å has been the glucose embedment method of Unwin and Henderson. We have recently been successful in obtaining high resolution electron diffraction patterns of purple membrane (PM) in ice. Routine preparation of membranes was facilitated by the use of a double carbon film technique which permitted controlled evaporation of the solution. Rapid freezing was accomplished by immediately submerging these preparations into LN2 - Specimens prepared in this way were inserted into a JEOL 100-B microscope using a cryo-transfer device and observed at temperatures of -130°C using a LN2 cold stage.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

The ultrastructure of coccoliths from the marine alga Emiliania huxleyi (Lohmann) Hay and Mohler: an ultra-high resolution electron microscope study

1983 ◽  
Vol 219 (1215) ◽  
pp. 111-117 ◽  
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Emiliania Huxleyi ◽  
Growth Patterns ◽  
Lattice Image ◽  
Nucleation Sites ◽  
Resolution Electron ◽  
Lattice Images ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns

The calcite coccoliths from the alga Emiliania huxleyi (Lohmann) Hay and Mohler have been studied by ultra-high resolution electron microscopy. This paper describes the two different types of structure observed, one in the upper elements, the other in the basal plate, or lower element. The former consisted of small, microdomain structures of 300-500 Å (1 Å = 10 -10 m) in length with no strong orientation. At places along these elements, and particularly in the junction between stem and head pieces, triangular patterns of lattice fringes were observed indicating multiple nucleation sites in the structure. In contrast, the lower element consisted of a very thin single crystalline sheet of calcite which could be resolved into a two dimensional lattice image, shown by a computer program that is capable of simulating electron diffraction patterns and lattice images to be a [421] zone of calcite. A possible mechanism for these growth patterns in the formation of coccoliths is discussed, together with the relevance of such mechanisms to biomineralization generally.

Atomic structure of YB56 studied by digital high-resolution electron microscopy and electron diffraction

2001 ◽  
Vol 16 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Takeo Oku ◽  
Jan-Olov Bovin ◽  
Iwami Higashi ◽  
Takaho Tanaka ◽  
Yoshio Ishizawa
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
High Resolution Electron Microscopy ◽  
Charge Coupled Device ◽  
X Ray ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Diffraction Patterns ◽  
Simulated Images

Atomic positions for Y atoms were determined by using high-resolution electron microscopy and electron diffraction. A slow-scan charge-coupled device camera which had high linearity and electron sensitivity was used to record high-resolution images and electron diffraction patterns digitally. Crystallographic image processing was applied for image analysis, which provided more accurate, averaged Y atom positions. In addition, atomic disordering positions in YB56 were detected from the differential images between observed and simulated images based on x-ray data, which were B24 clusters around the Y-holes. The present work indicates that the structure analysis combined with digital high-resolution electron microscopy, electron diffraction, and differential images is useful for the evaluation of atomic positions and disordering in the boron-based crystals.

High Resolution Electron Microscopy of Incommensurate Superlattices

1981 ◽  
Vol 39 ◽  
pp. 102-105
Author(s):  
Sumio Iijima ◽  
Yoshio Bando
Keyword(s):  
High Resolution ◽  
Periodic Structures ◽  
High Resolution Electron Microscopy ◽  
Crystal Structure Analysis ◽  
Imaging Method ◽  
Resolution Electron ◽  
Incommensurate Structures ◽  
Matrix Lattice ◽  
Diffraction Patterns ◽  
Types Of Information

Diffraction patterns of crystals having long period superlattices are described by their matrix lattice reflections, M = ha* + kb* + lc*, and a set of satellite reflections S appearing around each matrix reflection, which are characterized by S = m1a* + m2b* + m3c*. For usual superstructures the m's become rational numbers but for certain superstructures they are irrational. The latter are called the incommensurate superstructures. Crystal structure analysis by the conventional diffraction methods is based on perfectly periodic structures and generally cannot be applied to the crystals having the irrational superstructure periodicities. This paper deals with the study of such crystals using the high resolution lattice imaging method and the types of information obtained are discussed. It was intended that the study not only supplement the information on statistically averaged structures obtained from diffraction data but also provide further understanding of the incommensurate structures.

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