Showing papers by "Peter M. Colman published in 1976"
TL;DR: From these structures a hypothetical liganded antibody molecule has been constructed, which is assumed to be rigid, while in the Fc fragment both CH3 and CH2 show the immunoglobulin fold.
Abstract: The crystal structures of a human IgG antibody molecule Kol and a human Fc fragment have been determined at 4-A and 3.4-A resolution respectively, by isomorphous replacement. The electron-density maps were interpreted in terms of immunoglobulin domains based on the Rei and McPC 603 models (Kol) and by model-building (Fc). The Fab parts of Kol have a different quaternary structure from that observed in isolated crystalline Fab fragments, there being no longitudinal V-C contact in Kol. The Fc part C terminal to the hinge is disordered in the Kol crystals. It is suggested that the Kol molecule is flexible in solution, whereas fragments are rigid. In the Fc fragment both CH3 and CH2 show the immunoglobulin fold. The CH3 dimer aggregates as CH1-CL while CH2 are widely separated from each other. The carbohydrate bound to Fc is in fixed position. From these structures a hypothetical liganded antibody molecule has been constructed, which is assumed to be rigid.
412 citations
TL;DR: An electron density map at 5 A resolution of the human myeloma protein Kol shows 'a quaternary structure different from previously reported Fab fragments and provides evidence for flexibility in the switch peptides between variable and constant domains on heavy and light chains.
139 citations
TL;DR: The crystal structure analysis of a human Fc fragment was pursued to 3.5 A resolution and a complete model was built and refined into the isomorphous Fourier map, showing the immunoglobulin fold and the characteristic distribution of contact residues.
Abstract: The crystal structure analysis of a human Fc fragment was pursued to 3.5 A resolution and a complete model was built and refined into the isomorphous Fourier map. The CH2 and CH3 domains show the immunoglobulin fold, with CH3 being closely similar to CH1, but CH2 intermediate in structure between V and CH3. The carbohydrate is rigidly attached to CH2, covering the C face. CH3 dimerizes as CH1-CL, but CH2 has no contact to the second chain. Residues involved in the lateral CH3-CH3 and the longitudinal CH3-CH2 contact are conserved in Ig classes and sub-classes. In IgM and IgE the two C-terminal domains also show this characteristic distribution of contact residues.
117 citations
TL;DR: The crystal structure of a human Fc fragment was analysed at 4 A resolution and a partial interpretation of the electron-density map in terms of domain structure was possible.
Abstract: The crystal structure of a human Fc fragment was analysed at 4 A resolution. A partial interpretation of the electron-density map in terms of domain structure was possible. The molecule has the shape of a mickey mouse. The spherical domain was interpreted visually and by domain Patterson function interpretation as the CH3 dimer. This dimer resembles closely the CH1-CL dimer found in Fab structures. The ellipsoidal "ears" of the molecule represent the CH2 domains. They are widely separated from each other, but closely connected to CH3. Their tertiary structure must be different from CH1, as Patterson domain interpretations were unsuccessful. A chain tracing in CH2 was not yet possible.
52 citations
12 citations
01 Jan 1976
TL;DR: The crystal structures of a human IgG antibody molecule Kol and a human Fc fragment have been determined at 4 A and 35 A resolution respectively by isomorphous replacement as mentioned in this paper, which is the state-of-the-art method.
Abstract: The crystal structures of a human IgG antibody molecule Kol and a human Fc fragment have been determined at 4 A and 35 A resolution respectively by isomorphous replacement
6 citations
Journal Article•
5 citations
15 Apr 1976
TL;DR: Calculations with the proposed model for the arrangement of monomers within the tetramer and of tetramers in the unit cell have shown that these spurious symmetries result from the nonspecific overlap of protein-protein and solvent-solvent cross vectors.
Abstract: Native crystallographic data of tetrameric phosphorylase a crystals, space group P21; have been collected photographically to 3 a resolution. These data have been used in Patterson search methods in reciprocal and real space.
4 citations