scholarly journals Determination of the sedimentation coefficient of vaccinia virus DNA by analytical ultracentrifugation

1974 ◽  
Vol 1 (7) ◽  
pp. 901-906
Author(s):  
J. Grange
Keyword(s):  
Vaccinia Virus ◽  
Analytical Ultracentrifugation ◽  
Sedimentation Coefficient

Nonproteolyzed Form of DNA-Polymerase ε from T-Cell Spontaneous Lymphoma of Sprague-Dawley Inbred Rat: Isolation and Characterization

1998 ◽  
Vol 63 (5) ◽  
pp. 723-731 ◽  
Author(s):  
Gabriel Birkuš ◽  
Pavel Kramata ◽  
Ivan Votruba ◽  
Berta Otová ◽  
Miroslav Otmar ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Sedimentation Coefficient ◽  
Isolation Procedure ◽  
Sprague Dawley ◽  
Nucleotide Analogs ◽  
Isolation And Characterization ◽  
Inbred Rats ◽  
Catalyzed Reactions ◽  
Inbred Rat

Using a simple isolation procedure and selective assay for the determination of enzyme activity the nonproteolyzed and proteolyzed form of DNA-polymerase ε (pol ε and pol ε*) from the lymphoma of Sprague-Dawley inbred rats were purified. Nonproteolyzed pol ε is composed of two subunits (240 000 and 50 000) with sedimentation coefficient 10.5 S, while the subunit composition of pol ε* was 145 000 and 73 000. Estimated Km values for dATP and dGTP as well as Ki values for acyclic nucleotide analogs (PMEApp, HPMPApp and PMEDAPpp) in pol ε and pol ε* catalyzed reactions have shown that a proteolysis probably does not affect pol ε binding site for dNTPs. Both enzymes (pol ε and pol ε*) possess 3'-5'-exonuclease activity with different Km for 3'-OH end of template poly dA-oligo dT18 (1.6 μmol/l and 0.36 μmol/l, respectively).

Osmotic Pressure and Phase Boundary Determination of Multiphase Systems by Analytical Ultracentrifugation

ChemPhysChem ◽  
2008 ◽  
Vol 9 (6) ◽  
pp. 882-890 ◽  
Author(s):  
Miles G. Page ◽  
Thomas Zemb ◽  
Monique Dubois ◽  
Helmut Cölfen
Keyword(s):  
Phase Boundary ◽  
Osmotic Pressure ◽  
Analytical Ultracentrifugation ◽  
Boundary Determination ◽  
Multiphase Systems

scholarly journals Measurement of length distribution of beta-lactoglobulin fibrils by multiwavelength analytical ultracentrifugation

2020 ◽  
Vol 49 (8) ◽  
pp. 745-760 ◽  
Author(s):  
Maximilian J. Uttinger ◽  
Timon R. Heyn ◽  
Uwe Jandt ◽  
Simon E. Wawra ◽  
Bettina Winzer ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Amyloid Fibrils ◽  
Analytical Ultracentrifugation ◽  
Length Distribution ◽  
Sedimentation Coefficient ◽  
Size Reduction ◽  
Diameter Distribution ◽  
Cylindrical Shape ◽  
Modal Values ◽  
Beta Lactoglobulin

AbstractThe whey protein beta-lactoglobulin is the building block of amyloid fibrils which exhibit a great potential in various applications. These include stabilization of gels or emulsions. During biotechnological processing, high shear forces lead to fragmentation of fibrils and therefore to smaller fibril lengths. To provide insight into such processes, pure straight amyloid fibril dispersions (prepared at pH 2) were produced and sheared using the rotor stator setup of an Ultra Turrax. In the first part of this work, the sedimentation properties of fragmented amyloid fibrils sheared at different stress levels were analyzed with mulitwavelength analytical ultracentrifugation (AUC). Sedimentation data analysis was carried out with the boundary condition that fragmented fibrils were of cylindrical shape, for which frictional properties are known. These results were compared with complementary atomic force microscopy (AFM) measurements. We demonstrate how the sedimentation coefficient distribution from AUC experiments is influenced by the underlying length and diameter distribution of amyloid fibrils.In the second part of this work, we show how to correlate the fibril size reduction kinetics with the applied rotor revolution and the resulting energy density, respectively, using modal values of the sedimentation coefficients obtained from AUC. Remarkably, the determined scaling laws for the size reduction are in agreement with the results for other material systems, such as emulsification processes or the size reduction of graphene oxide sheets.

scholarly journals Sedimentation coefficient distributions of large particles

The Analyst ◽  
2016 ◽  
Vol 141 (14) ◽  
pp. 4400-4409 ◽  
Author(s):  
Peter Schuck
Keyword(s):  
Analytical Ultracentrifugation ◽  
Sedimentation Coefficient ◽  
Mathematical Framework ◽  
Analysis Methods ◽  
Large Particles

A uniform mathematical framework for sedimentation coefficient distributions in analytical ultracentrifugation establishes new relationships and resolves differences in analysis methods.

Strahlenempfindlichkeit von Bakteriophagen-DNS /Radiation sensitivity of Bacteriophage DNA

1969 ◽  
Vol 24 (7) ◽  
pp. 885-893 ◽  
Author(s):  
Thérèse Coquerelle ◽  
Leuthold Bohne ◽  
Ulrich Hagen ◽  
Jürgen Merkwitz
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Linear Part ◽  
Sedimentation Coefficient ◽  
Radiation Sensitivity ◽  
Quadratic Term ◽  
Molecular Weight Distributions ◽  
Γ Rays ◽  
Higher Doses

DNA isolated from Coli bacteriophage T1 was irradiated in 0.165 ᴍ NaCl with γ-rays. The molecular weight was determined by measurement of the sedimentation coefficient and viscosity. An analysis of the boundary permits the determination of the sedimentation distribution. The distribution of sedimentation coefficients obtained at various DNA concentrations were extrapolated to zero concentration and were transformed into molecular weight distributions. These were used to calculate the weight average molecular weight Mw and the number average molecular weight Mn.The molecular weight of T1-DNA was found to be 32· 106. After irradiation at a concentration of 200 μg/ml, double breaks as well as intermolecular crosslinks could be determined. The number of double breaks showed a rise with dose that can best be described as composed of a linear and a quadratic term. At low doses the crosslinks increase linearly, the rate being approximately half of that for the linear part of the double breaks. After higher doses, where most of the molecules are degraded, apparently no additional crosslinks are produced. No crosslinks were seen in DNA degraded by DNase. The influence of the DNA concentration on the degradation and the formation of crosslinks is discussed.

scholarly journals Structure, Subunit Topology, and Actin-binding Activity of the Arp2/3 Complex from Acanthamoeba

1997 ◽  
Vol 136 (2) ◽  
pp. 331-343 ◽  
Author(s):  
R. Dyche Mullins ◽  
Walter F. Stafford ◽  
Thomas D. Pollard
Keyword(s):  
Electron Micrographs ◽  
Actin Filaments ◽  
Analytical Ultracentrifugation ◽  
Fluorescent Antibody ◽  
Complex Molecule ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Leading Edge ◽  
Actin Binding ◽  
Filament Bundles

The Arp2/3 complex, first isolated from Acanthamoeba castellani by affinity chromatography on profilin, consists of seven polypeptides; two actinrelated proteins, Arp2 and Arp3; and five apparently novel proteins, p40, p35, p19, p18, and p14 (Machesky et al., 1994). The complex is homogeneous by hydrodynamic criteria with a Stokes' radius of 5.3 nm by gel filtration, sedimentation coefficient of 8.7 S, and molecular mass of 197 kD by analytical ultracentrifugation. The stoichiometry of the subunits is 1:1:1:1:1:1:1, indicating the purified complex contains one copy each of seven polypeptides. In electron micrographs, the complex has a bilobed or horseshoe shape with outer dimensions of ∼13 × 10 nm, and mathematical models of such a shape and size are consistent with the measured hydrodynamic properties. Chemical cross-linking with a battery of cross-linkers of different spacer arm lengths and chemical reactivities identify the following nearest neighbors within the complex: Arp2 and p40; Arp2 and p35; Arp3 and p35; Arp3 and either p18 or p19; and p19 and p14. By fluorescent antibody staining with anti-p40 and -p35, the complex is concentrated in the cortex of the ameba, especially in linear structures, possibly actin filament bundles, that lie perpendicular to the leading edge. Purified Arp2/3 complex binds actin filaments with a Kd of 2.3 μM and a stoichiometry of approximately one complex molecule per actin monomer. In electron micrographs of negatively stained samples, Arp2/3 complex decorates the sides of actin filaments. EDC/NHS cross-links actin to Arp3, p35, and a low molecular weight subunit, p19, p18, or p14. We propose structural and topological models for the Arp2/3 complex and suggest that affinity for actin filaments accounts for the localization of complex subunits to actinrich regions of Acanthamoeba.

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