Neutron scattering studies of nucleosome structure at low ionic strength

Biochemistry ◽  
1983 ◽  
Vol 22 (21) ◽  
pp. 4916-4923 ◽  
Author(s):  
Edward C. Uberbacher ◽  
Venkatraman Ramakrishnan ◽  
Donald E. Olins ◽  
Gerard J. Bunick
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Nucleosome Structure ◽  
Low Ionic Strength

Small angle neutron scattering studies of the structure of nucleosome cores at low ionic strength

Physica B+C ◽  
1983 ◽  
Vol 120 (1-3) ◽  
pp. 436-439
Author(s):  
Kazuei Mita ◽  
Mitsuo Zama ◽  
Sachiko Ichimura ◽  
Nobuo Niimura ◽  
Keisuke Kaji ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Low Ionic Strength

scholarly journals Visualization of nucleosomes in thin sections by stereo electron microscopy.

1980 ◽  
Vol 87 (3) ◽  
pp. 833-836 ◽  
Author(s):  
A L Olins ◽  
D E Olins ◽  
H Zentgraf ◽  
W W Franke
Keyword(s):  
Electron Microscopy ◽  
Ionic Strength ◽  
Electron Micrographs ◽  
High Magnification ◽  
Thin Sections ◽  
Nucleosome Structure ◽  
The Reformation ◽  
The Stability ◽  
Chicken Erythrocytes ◽  
Low Ionic Strength

Nucleosomes (approximately diameter) were clearly visualized in thin sections (approximately 0.1 micrometer thick) of isolated chicken erythrocytes. The cells were lysed and fixed in low ionic strength buffers that maintained the chromatin as dispersed filaments and prevented the reformation of supranucleosomal structures. Stereo electron micrographs at high magnification demonstrate the stability of nucleosome structure in the dispersed chromatin state during fixation, dehydration, and embedding.

Neutron Scattering from Charged Polymer Latices

1986 ◽  
Vol 79 ◽  
Author(s):  
John B. Hayter
Keyword(s):  
Ionic Strength ◽  
Neutron Scattering ◽  
Volume Fraction ◽  
Low Density ◽  
Latex Particles ◽  
Size Number ◽  
Particle Potential ◽  
Charged Polymer ◽  
Low Ionic Strength ◽  
Polymer Latex

AbstractAqueous suspensions of charged polymer latex particles exhibit several forms of ordered structure, the particular form depending on the size, number density and charge of the latex particles, and on the ionic strength of the aqueous medium. At low ionic strength, the inter-particle potential may become sufficiently long-ranged to generate crystalline order, which usually shows bcc symmetry at low density and becomes fcc above about 3% volume fraction of latex in the system. As the ionic strength increases, the crystalline structure melts, and ordered liquid structures develop. Light scattering may be used to study these structures at low density, but at higher density, where the opacity of the suspensions renders optical techniques intractable, neutron scattering must be used.This paper will review some of the recent small-angle neutron scattering experiments on polymer latex suspensions, in the light of new theoretical methods which permit in situ analysis of the particle size and charge. The discussion will also encompass new experimental methods for studying latex structures under dynamic shear conditions.

Conformational Transitions in Escherichia coli Ribosomal RNAs as Visualized by Dedicated STEM

1988 ◽  
Vol 46 ◽  
pp. 176-177
Author(s):  
J.S. Wall ◽  
V. Maridiyan ◽  
S. Tumminia ◽  
J. Hairifeld ◽  
M. Boublik
Keyword(s):  
Ionic Strength ◽  
Three Dimensional ◽  
Conformational Transitions ◽  
Dark Field ◽  
Dimensional Structure ◽  
Ribosomal Rnas ◽  
Field Mode ◽  
Freeze Dried ◽  
High Resolution Images ◽  
Low Ionic Strength

The high contrast in the dark-field mode of dedicated STEM, specimen deposition by the wet film technique and low radiation dose (1 e/Å2) at -160°C make it possible to obtain high resolution images of unstained freeze-dried macromolecules with minimal structural distortion. Since the image intensity is directly related to the local projected mass of the specimen it became feasible to determine the molecular mass and mass distribution within individual macromolecules and from these data to calculate the linear density (M/L) and the radii of gyration.2 This parameter (RQ), reflecting the three-dimensional structure of the macromolecular particles in solution, has been applied to monitor the conformational transitions in E. coli 16S and 23S ribosomal RNAs in solutions of various ionic strength.In spite of the differences in mass (550 kD and 1050 kD, respectively), both 16S and 23S RNA appear equally sensitive to changes in buffer conditions. In deionized water or conditions of extremely low ionic strength both appear as filamentous structures (Fig. la and 2a, respectively) possessing a major backbone with protruding branches which are more frequent and more complex in 23S RNA (Fig. 2a).

An Evaluation of a Plasma Fractionation System

1960 ◽  
Vol 4 (01) ◽  
pp. 031-044
Author(s):  
George Y. Shinowara ◽  
E. Mary Ruth
Keyword(s):  
Biological Activity ◽  
Ionic Strength ◽  
Plasma Proteins ◽  
High Concentration ◽  
Significant Evidence ◽  
Native Proteins ◽  
Mobility Data ◽  
Fractionation Procedure ◽  
The Individual ◽  
Low Ionic Strength

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.

scholarly journals A novel procedure for the rapid purification of plastocyanin from pea (Pisum sativum) leaves

1981 ◽  
Vol 193 (1) ◽  
pp. 375-378 ◽  
Author(s):  
A R Ashton ◽  
L E Anderson
Keyword(s):  
Ionic Strength ◽  
Pisum Sativum ◽  
Deae Cellulose ◽  
High Concentrations ◽  
Rapid Purification ◽  
Low Ionic Strength

Plastocyanin is soluble at high concentrations (greater than 3 M) of (NH4)2SO4 but under these conditions will adsorb tightly to unsubstituted Sepharose beads. This observation was utilized to purify plastocyanin from pea (Pisum sativum) in two chromatographic steps. Sepharose-bound plastocyanin was eluted with low-ionic-strength buffer and subsequently purified to homogeneity by DEAE-cellulose chromatography.

scholarly journals Crystallization of tuna ferricytochrome c at low ionic strength.

1990 ◽  
Vol 265 (8) ◽  
pp. 4177-4180
Author(s):  
M H Walter ◽  
E M Westbrook ◽  
S Tykodi ◽  
A M Uhm ◽  
E Margoliash
Keyword(s):  
Ionic Strength ◽  
Ferricytochrome C ◽  
Low Ionic Strength

scholarly journals Reaction of Myosin with 1-Fluoro-2,4-dinitrobenzene at Low Ionic Strength

1969 ◽  
Vol 244 (3) ◽  
pp. 648-657 ◽  
Author(s):  
M Bárány ◽  
G Bailin ◽  
K Bárány
Keyword(s):  
Ionic Strength ◽  
Low Ionic Strength
Sign in / Sign up

Export Citation Format

Share Document