IMR Press / FBL / Volume 28 / Issue 3 / DOI: 10.31083/j.fbl2803046
Open Access Original Research
Amyloid Formation of Stefin B Protein Studied by Infrared Spectroscopy
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1 Theory Department, National Institute of Chemistry, SI-1000 Ljubljana, Slovenia
2 Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
3 Department of Biotechnology and Systems Biology, National Institute of Biology, SI-1000 Ljubljana, Slovenia
*Correspondence: (Jože Grdadolnik)
Front. Biosci. (Landmark Ed) 2023, 28(3), 46;
Submitted: 23 December 2022 | Revised: 1 February 2023 | Accepted: 23 February 2023 | Published: 6 March 2023
(This article belongs to the Special Issue Protein Folding, Design and Aggregation: New Aspects and Uses)
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.

Background: Stefin B, an established model protein for studying the stability and mechanism of protein folding, was used for monitoring protein aggregation and formation of amyloid structure by infrared spectroscopy. Methods: The analyses of the integral intensities of the low frequency part of the Amide I band, which is directly connected to the appearance of the cross-β structure reveals the temperature but not pH dependence of stefin B structure. Results: We show that pH value has significant role in the monomer stability of stefin B. Protein is less stable in acidic environment and becomes more stable in neutral or basic conditions. While in the case of the Amide I band area analysis we apply only spectral regions characteristic for only part of the protein in cross-β structure, the temperature study using multivariate curve resolution (MCR) analysis contains also information about the protein conformation states which do not correspond to native protein nor protein in cross-β structure. Conclusions: These facts results in the slightly different shapes of fitted sigmoid functions fitted to the weighted amount of the second basic spectrum (sc2), which is the closed approximation of the protein spectra with cross-β structure. Nevertheless, the applied method detects the initial change of the protein structure. Upon the analysis of infrared data a model for stefin B aggregation is proposed.

stefin B
amyloid formation
infrared spectroscopy
structure analysis
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P1-0010/Slovenian Research Agency (ARRS), Slovenia
J1-1705/Slovenian Research Agency (ARRS), Slovenia
Fig. 1.
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