Abstract：
:The so-called 'H-fragment' of insulin is an extremely amyloidogenic double chain peptide consisting of the N-terminal parts of A-chain and B-chain linked by a disulfide bond between Cys-7A and Cys-7B. Here, we conduct a detailed investigation of the self-association behavior of H-fragment monomers into amyloid-like fibrils using kinetic assays, infrared spectroscopy, circular dichroism (CD), atomic force microscopy (AFM) and molecular dynamics (MD) simulations. Unlike the intact predominantly α-helical insulin, H-fragment remains in a disordered state in aqueous solutions. Its aggregation accelerates with acidification of the environment leading, at pH 1.9, to the formation of thin and structurally homogenous fibrils with the infrared features typical for parallel β-sheet conformation. According to time-lapse AFM morphological analysis both secondary nucleation and fragmentation are involved in later stages of H-fibrils' self-assembly. Based on the low nucleation order (two) obtained from the global fitting of kinetic data, realistic all-atom MD simulations of pairs of interacting H-fragment monomers were subsequently carried out. The molecular self-association scenario emerging from these simulations implicates the intrinsic conformational instability of H-monomer in its tendency to aggregate and form intermolecular β-sheet structure. Our findings provide the new mechanistic context for studies of insulin misfolding and aggregation.
journal_name
Int J Biol Macromoljournal_title
International journal of biological macromoleculesauthors
Dec R,Koliński M,Kouza M,Dzwolak Wdoi
10.1016/j.ijbiomac.2020.02.153subject
Has Abstractpub_date
2020-05-01 00:00:00pages
894-903eissn
0141-8130issn
1879-0003pii
S0141-8130(20)30852-7journal_volume
150pub_type
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
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journal_title：International journal of biological macromolecules
pub_type： 杂志文章
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journal_title：International journal of biological macromolecules
pub_type： 杂志文章
doi：10.1016/j.ijbiomac.2020.02.313
更新日期：2020-06-15 00:00:00
