Document Detail

An ultra-specific avian antibody to phosphorylated tau protein reveals a unique mechanism for phosphoepitope recognition.
MedLine Citation:
PMID:  23148212     Owner:  NLM     Status:  MEDLINE    
Highly specific antibodies to phosphoepitopes are valuable tools to study phosphorylation in disease states, but their discovery is largely empirical, and the molecular mechanisms mediating phosphospecific binding are poorly understood. Here, we report the generation and characterization of extremely specific recombinant chicken antibodies to three phosphoepitopes on the Alzheimer disease-associated protein tau. Each antibody shows full specificity for a single phosphopeptide. The chimeric IgG pT231/pS235_1 exhibits a K(D) of 0.35 nm in 1:1 binding to its cognate phosphopeptide. This IgG is murine ortholog-cross-reactive, specifically recognizing the pathological form of tau in brain samples from Alzheimer patients and a mouse model of tauopathy. To better understand the underlying binding mechanisms allowing such remarkable specificity, we determined the structure of pT231/pS235_1 Fab in complex with its cognate phosphopeptide at 1.9 Å resolution. The Fab fragment exhibits novel complementarity determining region (CDR) structures with a "bowl-like" conformation in CDR-H2 that tightly and specifically interacts with the phospho-Thr-231 phosphate group, as well as a long, disulfide-constrained CDR-H3 that mediates peptide recognition. This binding mechanism differs distinctly from either peptide- or hapten-specific antibodies described to date. Surface plasmon resonance analyses showed that pT231/pS235_1 binds a truly compound epitope, as neither phosphorylated Ser-235 nor free peptide shows any measurable binding affinity.
Heather H Shih; Chao Tu; Wei Cao; Anne Klein; Renee Ramsey; Brian J Fennell; Matthew Lambert; Deirdre Ní Shúilleabháin; Bénédicte Autin; Eugenia Kouranova; Sri Laxmanan; Steven Braithwaite; Leeying Wu; Mostafa Ait-Zahra; Anthony J Milici; Jo Ann Dumin; Edward R LaVallie; Maya Arai; Christopher Corcoran; Janet E Paulsen; Davinder Gill; Orla Cunningham; Joel Bard; Lydia Mosyak; William J J Finlay
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-11-12
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  287     ISSN:  1083-351X     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-31     Completed Date:  2013-03-25     Revised Date:  2014-01-09    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  44425-34     Citation Subset:  IM    
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MeSH Terms
Alzheimer Disease / genetics,  metabolism*
Amino Acid Sequence
Antibodies / chemistry,  genetics,  immunology*
Brain / metabolism
Epitopes / chemistry,  genetics,  immunology*
Immunoglobulin G / chemistry,  genetics,  immunology
Mice, Transgenic
Molecular Sequence Data
tau Proteins / chemistry,  genetics,  immunology*,  metabolism
Reg. No./Substance:
0/Antibodies; 0/Epitopes; 0/Immunoglobulin G; 0/MAPT protein, human; 0/tau Proteins

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