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Title: A Single Mutation at the Sheet Switch Region Results in Conformational Changes Favoring 6 Light-Chain Fibrillogenesis

Abstract

Systemic amyloid light-chain (LC) amyloidosis is a disease process characterized by the pathological deposition of monoclonal LCs in tissue. All LC subtypes are capable of fibril formation although {lambda} chains, particularly those belonging to the {lambda}6 type, are overrepresented. Here, we report the thermodynamic and in vitro fibrillogenic properties of several mutants of the {lambda}6 protein 6aJL2 in which Pro7 and/or His8 was substituted by Ser or Pro. The H8P and H8S mutants were almost as stable as the wild-type protein and were poorly fibrillogenic. In contrast, the P7S mutation decreased the thermodynamic stability of 6aJL2 and greatly enhanced its capacity to form amyloid-like fibrils in vitro. The crystal structure of the P7S mutant showed that the substitution induced both local and long-distance effects, such as the rearrangement of the VL (variable region of the light chain)-VL interface. This mutant crystallized in two orthorhombic polymorphs, P2{sub 1}2{sub 1}2{sub 1} and C222{sub 1}. In the latter, a monomer that was not arranged in the typical Bence-Jones dimer was observed for the first time. Crystal-packing analysis of the C222{sub 1} lattice showed the establishment of intermolecular {beta}-{beta} interactions that involved the N-terminus and {beta}-strand B and that these could be relevant inmore » the mechanism of LC fibril formation. Our results strongly suggest that Pro7 is a key residue in the conformation of the N-terminal sheet switch motif and, through long-distance interactions, is also critically involved in the contacts that stabilized the VL interface in {lambda}6 LCs.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
Sponsoring Org.:
DOE - OFFICE OF SCIENCE
OSTI Identifier:
1019809
Report Number(s):
BNL-95655-2011-JA
Journal ID: ISSN 0022-2836; JMOBAK; TRN: US201115%%445
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Journal of Molecular Biology
Additional Journal Information:
Journal Volume: 396; Journal Issue: 2; Journal ID: ISSN 0022-2836
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; CAPACITY; CHAINS; CONFORMATIONAL CHANGES; CRYSTAL STRUCTURE; DEPOSITION; DIMERS; DISEASES; IN VITRO; MONOMERS; MUTANTS; MUTATIONS; PROTEINS; RESIDUES; STABILITY; THERMODYNAMICS; national synchrotron light source

Citation Formats

Hernández-Santoyo, A, Del Pozo Yauner, L, Fuentes-Silva, D, Ortiz, E, Rudiño-Piñera, E, Sánchez-López, R, Horjales, E, Becerril, B, and Rodríguez-Romero, A. A Single Mutation at the Sheet Switch Region Results in Conformational Changes Favoring 6 Light-Chain Fibrillogenesis. United States: N. p., 2010. Web. doi:10.1016/j.jmb.2009.11.038.
Hernández-Santoyo, A, Del Pozo Yauner, L, Fuentes-Silva, D, Ortiz, E, Rudiño-Piñera, E, Sánchez-López, R, Horjales, E, Becerril, B, & Rodríguez-Romero, A. A Single Mutation at the Sheet Switch Region Results in Conformational Changes Favoring 6 Light-Chain Fibrillogenesis. United States. https://doi.org/10.1016/j.jmb.2009.11.038
Hernández-Santoyo, A, Del Pozo Yauner, L, Fuentes-Silva, D, Ortiz, E, Rudiño-Piñera, E, Sánchez-López, R, Horjales, E, Becerril, B, and Rodríguez-Romero, A. 2010. "A Single Mutation at the Sheet Switch Region Results in Conformational Changes Favoring 6 Light-Chain Fibrillogenesis". United States. https://doi.org/10.1016/j.jmb.2009.11.038.
@article{osti_1019809,
title = {A Single Mutation at the Sheet Switch Region Results in Conformational Changes Favoring 6 Light-Chain Fibrillogenesis},
author = {Hernández-Santoyo, A and Del Pozo Yauner, L and Fuentes-Silva, D and Ortiz, E and Rudiño-Piñera, E and Sánchez-López, R and Horjales, E and Becerril, B and Rodríguez-Romero, A},
abstractNote = {Systemic amyloid light-chain (LC) amyloidosis is a disease process characterized by the pathological deposition of monoclonal LCs in tissue. All LC subtypes are capable of fibril formation although {lambda} chains, particularly those belonging to the {lambda}6 type, are overrepresented. Here, we report the thermodynamic and in vitro fibrillogenic properties of several mutants of the {lambda}6 protein 6aJL2 in which Pro7 and/or His8 was substituted by Ser or Pro. The H8P and H8S mutants were almost as stable as the wild-type protein and were poorly fibrillogenic. In contrast, the P7S mutation decreased the thermodynamic stability of 6aJL2 and greatly enhanced its capacity to form amyloid-like fibrils in vitro. The crystal structure of the P7S mutant showed that the substitution induced both local and long-distance effects, such as the rearrangement of the VL (variable region of the light chain)-VL interface. This mutant crystallized in two orthorhombic polymorphs, P2{sub 1}2{sub 1}2{sub 1} and C222{sub 1}. In the latter, a monomer that was not arranged in the typical Bence-Jones dimer was observed for the first time. Crystal-packing analysis of the C222{sub 1} lattice showed the establishment of intermolecular {beta}-{beta} interactions that involved the N-terminus and {beta}-strand B and that these could be relevant in the mechanism of LC fibril formation. Our results strongly suggest that Pro7 is a key residue in the conformation of the N-terminal sheet switch motif and, through long-distance interactions, is also critically involved in the contacts that stabilized the VL interface in {lambda}6 LCs.},
doi = {10.1016/j.jmb.2009.11.038},
url = {https://www.osti.gov/biblio/1019809}, journal = {Journal of Molecular Biology},
issn = {0022-2836},
number = 2,
volume = 396,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}