Abstract
The blue-emissive antibody EP2-19G2 that has been elicited against trans-stilbene has unprecedented ability to produce bright luminescence and has been used as a biosensor in various applications. We show that the prolonged luminescence is not stilbene fluorescence. Instead, the emissive species is a charge-transfer excited complex of an anionic stilbene and a cationic, parallel pi-stacked tryptophan. Upon charge recombination, this complex generates exceptionally bright blue light. Complex formation is enabled by a deeply penetrating ligand-binding pocket, which in turn results from a noncanonical interface between the two variable domains of the antibody.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Antibodies, Monoclonal / chemistry*
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Antibodies, Monoclonal / genetics
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Antibodies, Monoclonal / immunology
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Antigen-Antibody Complex
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Binding Sites, Antibody
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Crystallization
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Crystallography, X-Ray
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Electrons*
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Fluorescence
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Fluorescence Polarization
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Haptens / chemistry
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Haptens / immunology
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Hydrophobic and Hydrophilic Interactions
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Immunoglobulin Variable Region / chemistry*
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Immunoglobulin Variable Region / immunology
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Ligands
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Luminescence
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Mutation
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Oxidation-Reduction
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Protein Structure, Tertiary
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Spectrometry, Fluorescence
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Spectrum Analysis
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Stilbenes / chemistry*
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Stilbenes / immunology
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Tryptophan / chemistry
Substances
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Antibodies, Monoclonal
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Antigen-Antibody Complex
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Haptens
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Immunoglobulin Variable Region
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Ligands
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Stilbenes
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Tryptophan