Influence of a Single Point Mutation in the Constant Domain of the Bence-Jones Protein BIF on Its Aggregation Properties
- 作者: Timchenko M.1, Timchenko A.2
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隶属关系:
- Institute of Theoretical and Experimental Biophysics
- Institute of Protein Research
- 期: 卷 83, 编号 2 (2018)
- 页面: 107-118
- 栏目: Article
- URL: https://journals.rcsi.science/0006-2979/article/view/151594
- DOI: https://doi.org/10.1134/S0006297918020037
- ID: 151594
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详细
Multiple myeloma nephropathy occurs due to the aggregate formation by monoclonal immunoglobulin light chains (Bence-Jones proteins) in kidneys of patients with multiple myeloma. The mechanism of amyloid deposit formation is still unclear. Earlier, the key role in the fibril formation has been assigned to the variable domains that acquired amyloidogenic properties as a result of somatic mutations. However, fibril formation by the Bence-Jones protein BIF was found to be the function of its constant domain. The substitution of Ser177 by Asn in the constant domain of the BIF protein is most likely an inherited than a somatic mutation. To study the role of this mutation in amyloidogenesis, the recombinant Bence-Jones protein BIF and its mutant with the N177S substitution typical for the known immunoglobulin Cκ allotypes Km1, Km1,2, and Km3 were isolated. The morphology of aggregates formed by the recombinant proteins under conditions similar to those occurring during the protein transport in bloodstream and its filtration into the renal glomerulus, in the distal tubules, and in the proximal renal tubules was analyzed by atomic force microscopy. The nature of the aggregates formed by BIF and its N177S mutant during incubation for 14 days at 37°C strongly differed and depended on both pH and the presence of a reducing agent. BIF formed fibrils at pH 7.2, 6.5, and 10.1, while the N177S mutant formed fibrils only at alkaline pH 10.1. The refolding of both proteins in the presence of 5 mM dithiothreitol resulted in the formation of branched structures.
作者简介
M. Timchenko
Institute of Theoretical and Experimental Biophysics
编辑信件的主要联系方式.
Email: maria_timchenko@mail.ru
俄罗斯联邦, Pushchino, Moscow Region, 142290
A. Timchenko
Institute of Protein Research
Email: maria_timchenko@mail.ru
俄罗斯联邦, Pushchino, Moscow Region, 142290