A Stable Mutant Predisposes Antibody Domains to Amyloid Formation through Specific Non-Native Interactions. Issue 6 (27th March 2016)

• Record Type: Journal Article
• Authors: Nokwe, Cardine N.; Hora, Manuel; Zacharias, Martin; Yagi, Hisashi; Peschek, Jirka; Reif, Bernd; Goto, Yuji; Buchner, Johannes
• Is Part Of: Journal of molecular biology. Volume 428:Issue 6(2016:Mar. 27)
• Page Start: 1315
• Page End: 1332
• Publication Date: 2016-03-27
• Subjects: LC light chain -- AL amyloid light chain -- MD molecular dynamics -- GdmCl guanidinium chloride -- ANS 1-anilino-8-naphthalene sulfonate -- ThT thioflavin T -- HSQC heteronuclear single quantum coherence -- EDTA ethylenediaminetetraacetic acid -- AUC analytical ultracentrifugation; protein folding and aggregation disease -- antibody amyloid -- point mutations -- domain stability -- immunoglobulin fold; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2016.01.015
• Languages: English
• ISSNs: 0022-2836

Abstract

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. Graphical abstract: Highlights: Why and how specific mutations induce amyloid formation in antibody light chain variable (VL ) domains remains poorly understood. Amyloid formation was observed for destabilized VL mutants through accumulation of non-native intermediates and through site-specific non-native interactions for stable mutants. These findings provide a new concept for the molecular mechanism of amyloid fibril formation.