1fbi
CRYSTAL STRUCTURE OF A CROSS-REACTION COMPLEX BETWEEN FAB F9.13.7 AND GUINEA-FOWL LYSOZYME
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OverviewOverview
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.
About this StructureAbout this Structure
1FBI is a Protein complex structure of sequences from Mus musculus and Numida meleagris. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a cross-reaction complex between Fab F9.13.7 and guinea fowl lysozyme., Lescar J, Pellegrini M, Souchon H, Tello D, Poljak RJ, Peterson N, Greene M, Alzari PM, J Biol Chem. 1995 Jul 28;270(30):18067-76. PMID:7629116
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