1FBI

CRYSTAL STRUCTURE OF A CROSS-REACTION COMPLEX BETWEEN FAB F9.13.7 AND GUINEA-FOWL LYSOZYME

Summary for 1FBI

• Entry DOI: 10.2210/pdb1fbi/pdb
• Descriptor: IGG1 F9.13.7 FAB (LIGHT CHAIN), IGG1 F9.13.7 FAB (HEAVY CHAIN), GUINEA FOWL LYSOZYME (3 entities in total)
• Functional Keywords: complex (antibody-antigen), complex (antibody-antigen) complex, complex (antibody/antigen)
• Biological source: Mus musculus (house mouse); More
• Cellular location: Isoform Secreted: Secreted: P01868; Secreted: P00704
• Total number of polymer chains: 6
• Total formula weight: 123593.65

Authors

Lescar, J.,Alzari, P.M. (deposition date: 1995-01-19, release date: 1995-02-27, Last modification date: 2024-11-20)

Primary citation

Lescar, J.,Pellegrini, M.,Souchon, H.,Tello, D.,Poljak, R.J.,Peterson, N.,Greene, M.,Alzari, P.M.
Crystal structure of a cross-reaction complex between Fab F9.13.7 and guinea fowl lysozyme.
J.Biol.Chem., 270:18067-18076, 1995

PubMed Abstract: The crystal structure of the complex between the cross-reacting antigen Guinea fowl lysozyme and the Fab from monoclonal antibody F9.13.7, raised against hen egg lysozyme, has been determined by x-ray diffraction to 3-A resolution. The antibody interacts with exposed residues of an alpha-helix and surrounding loops adjacent to the lysozyme active site cleft. The epitope of lysozyme bound by antibody F9.13.7 overlaps almost completely with that bound by antibody HyHEL10; the same 12 residues of the antigen interact with the two antibodies. The antibodies, however, have different combining sites with no sequence homology at any of their complementarity-determining regions and show a dissimilar pattern of cross-reactivity with heterologous antigens. Side chain mobility of epitope residues contributes to confer steric and electrostatic complementarity to differently shaped combining sites, allowing functional mimicry to occur. The capacity of two antibodies that have different fine specificities to bind the same area of the antigen emphasizes the operational character of the definition of an antigenic determinant. This example demonstrates that degenerate binding of the same structural motif does not require the existence of sequence homology or other chemical similarities between the different binding sites.

PubMed: 7629116
DOI: 10.1074/jbc.270.30.18067

Experimental method

X-RAY DIFFRACTION (3 Å)