Effects of a Concentration Dependence of the Sedimentation Coefficient in Velocity Ultracentrifugation

1956 ◽  
Vol 24 (5) ◽  
pp. 1084-1090 ◽  
Author(s):  
Hiroshi Fujita
Keyword(s):  
Concentration Dependence ◽  
Sedimentation Coefficient

Masking of the Fc region in human IgG4 by constrained X-ray scattering modelling: implications for antibody function and therapy

2010 ◽  
Vol 432 (1) ◽  
pp. 101-114 ◽  
Author(s):  
Yuki Abe ◽  
Jayesh Gor ◽  
Daniel G. Bracewell ◽  
Stephen J. Perkins ◽  
Paul A. Dalby
Keyword(s):  
Concentration Dependence ◽  
Solution Structure ◽  
Analytical Ultracentrifugation ◽  
Sedimentation Coefficient ◽  
Radius Of Gyration ◽  
X Ray ◽  
X Ray Scattering ◽  
Starting Point ◽  
Self Association ◽  
Ray Scattering

Of the four human IgG antibody subclasses IgG1–IgG4, IgG4 is of interest in that it does not activate complement and exhibits atypical self-association, including the formation of bispecific antibodies. The solution structures of antibodies are critical to understand function and therapeutic applications. Thus IgG4 was studied by synchrotron X-ray scattering. The Guinier X-ray radius of gyration RG increased from 5.0 nm to 5.1 nm with an increase of concentration. The distance distribution function P(r) revealed a single peak at 0.3 mg/ml, which resolved into two peaks that shifted to smaller r values at 1.3 mg/ml, even though the maximum dimension of IgG4 was unchanged at 17 nm. This indicated a small concentration dependence of the IgG4 solution structure. By analytical ultracentrifugation, no concentration dependence in the sedimentation coefficient of 6.4 S was observed. Constrained scattering modelling resulted in solution structural determinations that showed that IgG4 has an asymmetric solution structure in which one Fab–Fc pair is closer together than the other pair, and the accessibility of one side of the Fc region is masked by the Fab regions. The averaged distances between the two Fab–Fc pairs change by 1–2 nm with the change in IgG4 concentration. The averaged conformation of the Fab regions appear able to hinder complement C1q binding to the Fc region and the self-association of IgG4 through the Fc region. The present results clarify IgG4 function and provide a starting point to investigate antibody stability.

scholarly journals Quantifying the concentration dependence of sedimentation coefficients for globular macromolecules: a continuing age-old problem

2021 ◽  
Author(s):  
Donald J. Winzor ◽  
Vlad Dinu ◽  
David J. Scott ◽  
Stephen E. Harding
Keyword(s):  
Concentration Dependence ◽  
Diffusion Coefficients ◽  
Sedimentation Coefficient ◽  
Sedimentation Velocity ◽  
Translational Diffusion ◽  
Optical Systems ◽  
Coefficient Measurement ◽  
Retrospective Investigation ◽  
Linear Concentration

AbstractThis retrospective investigation has established that the early theoretical attempts to directly incorporate the consequences of radial dilution into expressions for variation of the sedimentation coefficient as a function of the loading concentration in sedimentation velocity experiments require concentration distributions exhibiting far greater precision than that achieved by the optical systems of past and current analytical ultracentrifuges. In terms of current methods of sedimentation coefficient measurement, until such improvement is made, the simplest procedure for quantifying linear s-c dependence (or linear concentration dependence of 1/s) for dilute systems therefore entails consideration of the sedimentation coefficient obtained by standard c(s), g*(s) or G(s) analysis) as an average parameter ($$ \overline{s} $$ s ¯ ) that pertains to the corresponding mean plateau concentration (following radial dilution) ($$ \overline{c} $$ c ¯ ) over the range of sedimentation velocity distributions used for the determination of $$ \overline{s} $$ s ¯ . The relation of this with current descriptions of the concentration dependence of the sedimentation and translational diffusion coefficients is considered, together with a suggestion for the necessary improvement in the optical system.

Concentration dependence of the properties of gelatin and iota-carrageenan systems at the gel point

1996 ◽  
Vol 93 ◽  
pp. 819-827 ◽  
Author(s):  
C Michon ◽  
G Cuvelier ◽  
B Launay ◽  
A Parker
Keyword(s):  
Concentration Dependence ◽  
Gel Point

TEMPERATURE AND CONCENTRATION DEPENDENCE OF THE SPECIFIC HEAT OF (ErxY1-x) Co2

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-273-C8-274 ◽  
Author(s):  
N. Pillmayr ◽  
G. Hilscher ◽  
E. Gratz ◽  
V. Sechovsky
Keyword(s):  
Specific Heat ◽  
Concentration Dependence

The Concentration Dependence of Hydrogen Diffusion in fcc TiHx, TiDxand YHx*

1992 ◽  
Vol 1 (1) ◽  
pp. 631-635
Author(s):  
U. Stuhr ◽  
D. Steinbinder ◽  
H. Wipf ◽  
B. Frick
Keyword(s):  
Concentration Dependence ◽  
Hydrogen Diffusion
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