Structure of an Fab fragment against a C-terminal peptide of hCG at 2.0 A resolution.
3A2 is an antibody raised against human chorionic gonadotropin and recognizes a linear epitope on the C-terminal peptide of the human chorionic gonadotropin beta-subunit. Its three-dimensional structure has been determined to 2-A resolution using molecular replacement and refined to a conventional R-factor of 18.2%. The protein exhibits the typical immunoglobulin fold, and the model contains 944 ordered water molecules and one sulfate ion. A comparison of the complementarity-determining regions of the Fab3A2 with those from the Protein Data Bank following the canonical structure method reveals a canonical main chain conformation. This antibody belongs to the canonical structure class (combination of canonical conformations of the complementarity determining loops) that shows a preference for haptens and not for peptides. However, the shape of the surface of the antigen binding loops resembles that of an anti-peptide antibody.
Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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Fotinou
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Beauchamp
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Emsley
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deHaan
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Schielen
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Isaacs
D000595:Amino Acid Sequence; D002460:Cell Line; D006063:Chorionic Gonadotropin / Q000737:chemistry*; D018360:Crystallography, X-Ray; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D006860:Hydrogen Bonding; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry* / Q000276:immunology; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D006063:Chorionic Gonadotropin; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; D010446:Peptide Fragments