1. Structural modelling of the DNAJB6 oligomeric chaperone shows a peptide-binding cleft lined with conserved S/T-residues at the dimer interface.
- Author
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Söderberg CAG, Månsson C, Bernfur K, Rutsdottir G, Härmark J, Rajan S, Al-Karadaghi S, Rasmussen M, Höjrup P, Hebert H, and Emanuelsson C
- Subjects
- Amyloid genetics, Amyloid beta-Peptides genetics, Biophysical Phenomena, HSP40 Heat-Shock Proteins genetics, Humans, Lysine chemistry, Mass Spectrometry, Models, Structural, Molecular Chaperones genetics, Molecular Dynamics Simulation, Nerve Tissue Proteins genetics, Protein Binding genetics, Protein Multimerization, Scattering, Small Angle, X-Ray Diffraction, Amyloid chemistry, Amyloid beta-Peptides chemistry, HSP40 Heat-Shock Proteins chemistry, Molecular Chaperones chemistry, Nerve Tissue Proteins chemistry, Protein Conformation
- Abstract
The remarkably efficient suppression of amyloid fibril formation by the DNAJB6 chaperone is dependent on a set of conserved S/T-residues and an oligomeric structure, features unusual among DNAJ chaperones. We explored the structure of DNAJB6 using a combination of structural methods. Lysine-specific crosslinking mass spectrometry provided distance constraints to select a homology model of the DNAJB6 monomer, which was subsequently used in crosslink-assisted docking to generate a dimer model. A peptide-binding cleft lined with S/T-residues is formed at the monomer-monomer interface. Mixed isotope crosslinking showed that the oligomers are dynamic entities that exchange subunits. The purified protein is well folded, soluble and composed of oligomers with a varying number of subunits according to small-angle X-ray scattering (SAXS). Elongated particles (160 × 120 Å) were detected by electron microscopy and single particle reconstruction resulted in a density map of 20 Å resolution into which the DNAJB6 dimers fit. The structure of the oligomer and the S/T-rich region is of great importance for the understanding of the function of DNAJB6 and how it can bind aggregation-prone peptides and prevent amyloid diseases.
- Published
- 2018
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