3ec5 | pdb_00003ec5
The crystal structure of Thioflavin-T (ThT) binding OspA mutant
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedA number of small organic molecules have been developed that bind to amyloid fibrils, a subset of which also inhibit fibrillization. Among these, the benzothiol dye Thioflavin-T (ThT) has been used for decades in the diagnosis of protein-misfolding diseases and in kinetic studies of self-assembly (fibrillization). Despite its importance, efforts to characterize the ThT-binding mechanism at the atomic level have been hampered by the inherent insolubility and heterogeneity of peptide self-assemblies. To overcome these challenges, we have developed a minimalist approach to designing a ThT-binding site in a "peptide self-assembly mimic" (PSAM) scaffold. PSAMs are engineered water-soluble proteins that mimic a segment of beta-rich peptide self-assembly, and they are amenable to standard biophysical techniques and systematic mutagenesis. The PSAM beta-sheet contains rows of repetitive amino acid patterns running perpendicular to the strands (cross-strand ladders) that represent a ubiquitous structural feature of fibril-like surfaces. We successfully designed a ThT-binding site that recapitulates the hallmarks of ThT-fibril interactions by constructing a cross-strand ladder consisting of contiguous tyrosines. The X-ray crystal structures suggest that ThT interacts with the beta-sheet by docking onto surfaces formed by a single tyrosine ladder, rather than in the space between adjacent ladders. Systematic mutagenesis further demonstrated that tyrosine surfaces across four or more beta-strands formed the minimal binding site for ThT. Our work thus provides structural insights into how this widely used dye recognizes a prominent subset of peptide self-assemblies, and proposes a strategy to elucidate the mechanisms of fibril-ligand interactions. Molecular mechanism of thioflavin-T binding to the surface of beta-rich peptide self-assemblies.,Biancalana M, Makabe K, Koide A, Koide S J Mol Biol. 2009 Jan 30;385(4):1052-63. Epub 2008 Nov 14. PMID:19038267[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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