scholarly journals Concentration Dependence of the Sedimentation Coefficient of Flexible Macromolecules in Dilute Solution: Poly(α-methylstyrene) and Polystyrene

1972 ◽  
Vol 3 (4) ◽  
pp. 421-430 ◽  
Author(s):  
Akira Kotera ◽  
Takahide Saito ◽  
Takeshi Hamada
Keyword(s):  
Concentration Dependence ◽  
Sedimentation Coefficient ◽  
Dilute Solution

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 Dilute Solution Properties of Monodisperse Poly(α-methyl styrene). I. Sedimentation Coefficient in Theta Solvent

1968 ◽  
Vol 41 (10) ◽  
pp. 2330-2336 ◽  
Author(s):  
Mitsuo Abe ◽  
Kuniaki Sakato ◽  
Takashi Kageyama ◽  
Masaaki Fukatsu ◽  
Michio Kurata
Keyword(s):  
Sedimentation Coefficient ◽  
Solution Properties ◽  
Dilute Solution ◽  
Dilute Solution Properties ◽  
Methyl Styrene ◽  
Theta Solvent
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