Structural conformations of nucleosomes at low ionic strength from flow birefringence and intrinsic viscosity

Biopolymers ◽  
1981 ◽  
Vol 20 (4) ◽  
pp. 719-752 ◽  
Author(s):  
Rodney E. Harrington
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Flow Birefringence ◽  
Low Ionic Strength

Challenges in Determining Intrinsic Viscosity Under Low Ionic Strength Solution Conditions

2017 ◽  
Vol 34 (4) ◽  
pp. 836-846 ◽  
Author(s):  
Mariya A. Pindrus ◽  
Steven J. Shire ◽  
Sandeep Yadav ◽  
Devendra S. Kalonia
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Low Ionic Strength

Viscosimetric studies of chitosan nitrate and chitosan chlorhydrate in acid free NaCl aqueous solution

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Cristóbal Lárez Velásquez ◽  
Joel Sánchez Albornoz ◽  
Enrique Millán Barrios
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Aqueous Medium ◽  
Intrinsic Viscosity ◽  
Free Acid ◽  
Film Formation ◽  
Stiffness Parameter ◽  
Low Ionic Strength

AbstractTwo salts of the biopolymer chitosan were prepared in aqueous medium by employing an excess of HCl or HNO3 in order to ensure neutralization of all NH2-chitosan groups. Chitosan salts were extensively dialyzed in dionised water and dried at 40 ºC until film formation. The films were characterized by thermogravimetry, FTIR and conductimetric tritration. QH+Cl− and QH+NO3− salts were viscosimetrically evaluated in free acid aqueous solutions in the presence of NaCl to control ionic strength of the medium. Unexpected high intrinsic viscosity values were obtained at low ionic strength when QH+NO3− salt were evaluated. Smidsrod´s approach was employed to estimate the stiffness parameter of both salts and B = 0.084 and 0.120 for QH+Cl− and QH+NO3−, respectively, were obtained.

Precollapse of T7 DNA by spermidine at low ionic strength: A linear dichroism and intrinsic viscosity study

Biopolymers ◽  
1984 ◽  
Vol 23 (12) ◽  
pp. 2835-2851 ◽  
Author(s):  
Walter A. Baase ◽  
Paul W. Staskus ◽  
Stuart A. Allison
Keyword(s):  
Ionic Strength ◽  
Intrinsic Viscosity ◽  
Linear Dichroism ◽  
Viscosity Study ◽  
Low Ionic Strength

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
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