title: A Stable Mutant Predisposes Antibody Domains to Amyloid Formation through Specific Non-Native Interactions.
abstract: The aggregation of mostly antibody light chain variable (VL) domains into amyloid fibrils in various tissues is the main cause of death in systemic amyloid light chain amyloidosis. Point mutations within the domain are important to shift the VL into the fibrillar pathway, but why and how only some site-specific mutations achieve this still remains elusive. We show here that both destabilizing and surprisingly stable mutants readily predispose an amyloid-resistant VL domain to amyloid formation. The decreased thermodynamic stability of the destabilizing mutant results in the accumulation of non-native intermediates that readily populate the amyloid state. Interestingly, the stable mutants establish site-specific non-native interactions with especially nearby serine/threonine residues that unexpectedly do not affect the folding behavior of the VL domain but rather readily induce and stabilize the fibril structure, a previously unrecognized mechanism. These findings provide a new concept for the molecular mechanism of amyloid fibril formation.
authors.affiliation: Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
authors.forename: Cardine N
authors.initials: CN
authors.lastname: Nokwe
authors.affiliation: Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany; Helmholtz-Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Hora
authors.affiliation: Center for Integrated Protein Science at the Department Physik, Technische Universität München, James-Franck-Strasse 1, D-85748 Garching, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Zacharias
authors.affiliation: Division of Protein Structural Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yagi
authors.affiliation: Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
authors.forename: Jirka
authors.initials: J
authors.lastname: Peschek
authors.affiliation: Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany; Helmholtz-Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Reif
authors.affiliation: Division of Protein Structural Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Goto
authors.affiliation: Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany. Electronic address: johannes.buchner@tum.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
mesh_terms: D000682:Amyloid / Q000235:genetics / Q000378:metabolism*; D000906:Antibodies / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism*; D066263:Protein Aggregation, Pathological; D055503:Protein Multimerization
chemical_list: D000682:Amyloid; D000906:Antibodies; D050505:Mutant Proteins
keywords: antibody amyloid; domain stability; immunoglobulin fold; point mutations; protein folding and aggregation disease