title: Alternative conformations of the Tau repeat domain in complex with an engineered binding protein.
abstract: The aggregation of Tau into paired helical filaments is involved in the pathogenesis of several neurodegenerative diseases, including Alzheimer disease. The aggregation reaction is characterized by conformational conversion of the repeat domain, which partially adopts a cross-β-structure in the resulting amyloid-like fibrils. Here, we report the selection and characterization of an engineered binding protein, β-wrapin TP4, targeting the Tau repeat domain. TP4 was obtained by phage display using the four-repeat Tau construct K18ΔK280 as a target. TP4 binds K18ΔK280 as well as the longest isoform of human Tau, hTau40, with nanomolar affinity. NMR spectroscopy identified two alternative TP4-binding sites in the four-repeat domain, with each including two hexapeptide motifs with high β-sheet propensity. Both binding sites contain the aggregation-determining PHF6 hexapeptide within repeat 3. In addition, one binding site includes the PHF6* hexapeptide within repeat 2, whereas the other includes the corresponding hexapeptide Tau(337-342) within repeat 4, denoted PHF6**. Comparison of TP4-binding with Tau aggregation reveals that the same regions of Tau are involved in both processes. TP4 inhibits Tau aggregation at substoichiometric concentration, demonstrating that it interferes with aggregation nucleation. This study provides residue-level insight into the interaction of Tau with an aggregation inhibitor and highlights the structural flexibility of Tau.
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany.
authors: Clara S R
authors: CSR
authors: Grüning
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany.
authors: Ewa A
authors: EA
authors: Mirecka
authors: Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany.
authors: Antonia N
authors: AN
authors: Klein
authors: German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, and; Center of Advanced European Studies And Research (CAESAR), 53175 Bonn, Germany.
authors: Eckhard
authors: E
authors: Mandelkow
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany.
authors: Dieter
authors: D
authors: Willbold
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany.
authors: Stephen F
authors: SF
authors: Marino
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany.
authors: Matthias
authors: M
authors: Stoldt
authors: Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany,. Electronic address: wolfgang.hoyer@uni-duesseldorf.de.
authors: Wolfgang
authors: W
authors: Hoyer
mesh_terms: D001665:Binding Sites; D006801:Humans; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D020449:Repetitive Sequences, Amino Acid; D016875:tau Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics
chemical_list: C054369:MAPT protein, human; D011994:Recombinant Proteins; D016875:tau Proteins
keywords: Alzheimer Disease; Amyloid; Nuclear Magnetic Resonance; Protein Aggregation; Protein Conformation; Protein Engineering; Protein Misfolding; Tau Protein (Tau)