caa a22 4500 528787195 20181214030152.0 cr unu---uuuuu 180924e20120314xx s 000 0 eng 10.3929/ethz-b-000048393 doi 10.1371/journal.pone.0033372 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/48393 In Vitro Aggregation Behavior of a Non-Amyloidogenic λ Light Chain Dimer Deriving from U266 Multiple Myeloma Cells [Elektronische Daten] [Paolo Arosio, Marta Owczarz, Thomas Müller-Späth, Paola Rognoni, Marten Beeg, Hua; id_orcid 0000-0002-2805-4612 Wu, Mario Salmona, Massimo Morbidelli] PLoS ONE Open access ethresearch Excessive production of monoclonal light chains due to multiple myeloma can induce aggregation-related disorders, such as light chain amyloidosis (AL) and light chain deposition diseases (LCDD). In this work, we produce a non-amyloidogenic IgE λ light chain dimer from human mammalian cells U266, which originated from a patient suffering from multiple myeloma, and we investigate the effect of several physicochemical parameters on the in vitro stability of this protein. The dimer is stable in physiological conditions and aggregation is observed only when strong denaturating conditions are applied (acidic pH with salt at large concentration or heating at melting temperature Tm at pH 7.4). The produced aggregates are spherical, amorphous oligomers. Despite the larger β-sheet content of such oligomers with respect to the native state, they do not bind Congo Red or ThT. The impossibility to obtain fibrils from the light chain dimer suggests that the occurrence of amyloidosis in patients requires the presence of the light chain fragment in the monomer form, while dimer can form only amorphous oligomers or amorphous deposits. No aggregation is observed after denaturant addition at pH 7.4 or at pH 2.0 with low salt concentration, indicating that not a generic unfolding but specific conformational changes are necessary to trigger aggregation. A specific anion effect in increasing the aggregation rate at pH 2.0 is observed according to the following order: SO4−≫Cl−>H2PO4−, confirming the peculiar role of sulfate in promoting protein aggregation. It is found that, at least for the investigated case, the mechanism of the sulfate effect is related to protein secondary structure changes induced by anion binding. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Arosio Paolo joint author Owczarz Marta joint author Müller-Späth Thomas joint author Rognoni Paola joint author Beeg Marten joint author Wu Hua; id_orcid 0000-0002-2805-4612 joint author Salmona Mario joint author Morbidelli Massimo joint author PLoS ONE Public Library of Science 7 (3), p. e33372 1932-6203 http://hdl.handle.net/20.500.11850/48393 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/48393 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Arosio Paolo joint author ETHRESEARCH 700 1- Owczarz Marta joint author ETHRESEARCH 700 1- Müller-Späth Thomas joint author ETHRESEARCH 700 1- Rognoni Paola joint author ETHRESEARCH 700 1- Beeg Marten joint author ETHRESEARCH 700 1- Wu Hua; id_orcid 0000-0002-2805-4612 joint author ETHRESEARCH 700 1- Salmona Mario joint author ETHRESEARCH 700 1- Morbidelli Massimo joint author ETHRESEARCH 773 0- PLoS ONE Public Library of Science 7 (3), p. e33372 1932-6203 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access