Biophys J, December 1999, p. 2902-2910, Vol. 77, No. 6

Novel Size-Independent Modeling of the Dilute Solution Conformation of the Immunoglobulin IgG Fab' Domain Using SOLPRO and ELLIPS

 ^*Departamento de Quimica Fisica, Facultad de Quimica, Universidad de Murcia, 30071 Murcia, Spain;  ^#National Centre for Macromolecular Hydrodynamics, University of Nottingham, School of Biological Sciences, Sutton Bonington LE12 5RD, England;  ^§Celltech Therapeutics, Bath Road, Slough, Berkshire, England; and  ^¶Biomolecular Structure and Modelling Unit, Department of Biochemistry and Molecular Biology, University of London, London WC1 6BT, England

The proliferation of hydrodynamic modeling strategies to represent the shape of quasirigid macromolecules in solution has been hampered by ambiguities caused by size. Universal shape parameters, independent of size, developed originally for ellipsoid modeling, are now available for modeling using the bead-shell approximation via the algorithm SOLPRO. This paper validates such a "size-independent" bead-shell approach by comparison with the exact hydrodynamics of 1) an ellipsoid of revolution and 2) a general triaxial ellipsoid (semiaxial ratios a/b, b/c) based on a fit using the routine ELLIPSE (Taylor et al., 1983. J. Mol. Graph. 1:30-38) to the chimeric (human/mouse) IgG Fab' B72.3; a similar fit is obtained for other Fabs. Size-independent application of the bead-shell approximation yields errors of only ~1% in frictional ratio based shape functions and ~3% in the radius of gyration. With the viscosity increment, errors have been reduced to ~3%, representing a significant improvement on earlier procedures. Combination of the Perrin frictional ratio function with the experimentally measured sedimentation coefficient for the same Fab' from B72.3 yields an estimate for the molecular hydration of the Fab' fragment of ~(0.43 ± 0.07) g/g. This value is compared to values obtained in a similar way for deoxyhemoglobin (0.44) and ribonuclease (0.27). The application of SOLPRO to the shape analysis of more complex macromolecules is indicated, and we encourage such size-independent strategies. The utility of modern sedimentation data analysis software such as SVEDBERG, DCDT, LAMM, and MSTAR is also clearly demonstrated.

Biophys J, December 1999, p. 2902-2910, Vol. 77, No. 6
© 1999 by the Biophysical Society   0006-3495/99/12/2902/09  $2.00

This article has been cited by other articles:

				Y. Lu, S. E. Harding, T. E. Michaelsen, E. Longman, K. G. Davis, A. Ortega, J. G. Grossmann, I. Sandlie, and J. Garcia de la Torre Solution Conformation of Wild-Type and Mutant IgG3 and IgG4 Immunoglobulins Using Crystallohydrodynamics: Possible Implications for Complement Activation Biophys. J., December 1, 2007; 93(11): 3733 - 3744. [Abstract] [Full Text] [PDF]

				Y. Lu, E. Longman, K. G. Davis, A. Ortega, J. G. Grossmann, T. E. Michaelsen, J. G. de la Torre, and S. E. Harding Crystallohydrodynamics of Protein Assemblies: Combining Sedimentation, Viscometry, and X-Ray Scattering Biophys. J., September 1, 2006; 91(5): 1688 - 1697. [Abstract] [Full Text] [PDF]

				A. H. Merry, R. J. C. Gilbert, D. A. Shore, L. Royle, O. Miroshnychenko, M. Vuong, M. R. Wormald, D. J. Harvey, R. A. Dwek, B. J. Classon, et al. O-Glycan Sialylation and the Structure of the Stalk-like Region of the T Cell Co-receptor CD8 J. Biol. Chem., July 11, 2003; 278(29): 27119 - 27128. [Abstract] [Full Text] [PDF]

				N. Mavaddat, D. W. Mason, P. D. Atkinson, E. J. Evans, R. J. C. Gilbert, D. I. Stuart, J. A. Fennelly, A. N. Barclay, S. J. Davis, and M. H. Brown Signaling Lymphocytic Activation Molecule (CDw150) Is Homophilic but Self-associates with Very Low Affinity J. Biol. Chem., September 1, 2000; 275(36): 28100 - 28109. [Abstract] [Full Text] [PDF]