4GLR

Structure of the anti-ptau Fab (pT231/pS235_1) in complex with phosphoepitope pT231/pS235

Summary for 4GLR

• Entry DOI: 10.2210/pdb4glr/pdb
• Related: 3BN9 3G6D 3GJE 3H42 3KYM 3MA9
• Descriptor: phospho-peptide, anti-ptau heavy chain, anti-ptau light chain, ... (5 entities in total)
• Functional Keywords: igg1 fab, anti-ptau antibody, phosphorylated tau peptide, phosphorylation, immune system
• Biological source: Gallus gallus (chicken); More
• Total number of polymer chains: 6
• Total formula weight: 95855.81

Authors

Tu, C.,Mosyak, L.,Bard, J. (deposition date: 2012-08-14, release date: 2012-11-21, Last modification date: 2023-09-13)

Primary citation

Shih, H.H.,Tu, C.,Cao, W.,Klein, A.,Ramsey, R.,Fennell, B.J.,Lambert, M.,Ni Shuilleabhain, D.,Autin, B.,Kouranova, E.,Laxmanan, S.,Braithwaite, S.,Wu, L.,Ait-Zahra, M.,Milici, A.J.,Dumin, J.A.,Lavallie, E.R.,Arai, M.,Corcoran, C.,Paulsen, J.E.,Gill, D.,Cunningham, O.,Bard, J.,Mosyak, L.,Finlay, W.J.
An Ultra-specific Avian Antibody to Phosphorylated Tau Protein Reveals a Unique Mechanism for Phosphoepitope Recognition.
J.Biol.Chem., 287:44425-44434, 2012

PubMed Abstract: 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.

PubMed: 23148212
DOI: 10.1074/jbc.M112.415935

Experimental method

X-RAY DIFFRACTION (1.9 Å)