Spectroscopic Evidence of the Salt-Induced Conformational Change around the Localized Electric Charges on the Protein Surface of Fibronectin Type III
| Autor: | Chikashi Ota, Shun-ichi Tanaka, Kazufumi Takano, Yui Fukuda |
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| Rok vydání: | 2020 |
| Předmět: |
Models
Molecular Conformational change Protein Conformation Fibronectin Type III Domain Static Electricity Salt (chemistry) 02 engineering and technology Fibronectin type III domain Sodium Chloride 010402 general chemistry 01 natural sciences Electrochemistry medicine Humans General Materials Science Thermal stability Binding site Spectroscopy chemistry.chemical_classification biology Chemistry Triad (anatomy) Surfaces and Interfaces 021001 nanoscience & nanotechnology Condensed Matter Physics Fibronectins 0104 chemical sciences Fibronectin medicine.anatomical_structure Structural change biology.protein Biophysics 0210 nano-technology |
| Zdroj: | Langmuir. 36:14243-14254 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/acs.langmuir.0c02367 |
| Popis: | The effect of salt on the electrostatic interaction of a protein is an important issue, because addition of salt affects protein stability and association/aggregation. Although adding salt is a generally recognized strategy to improve protein stability, this improvement does not necessarily occur. The lack of an effect upon the addition of salt was previously confirmed for the tenth fibronectin type III domain from human fibronectin (FN3) by thermal stability analysis. However, the detailed molecular mechanism is unknown. In the present study, by employing the negatively charged carboxyl triad on the surface of FN3 as a case study, the molecular mechanism of the inefficient NaCl effect on protein stability was experimentally addressed using spectroscopic methods. Complementary analysis using Raman spectroscopy and 8-anilino-1-naphthalenesulfonic acid fluorescence revealed the three-phase behavior of the salt-protein interaction between NaCl and FN3 over a wide salt concentration range from 100 mM to 4.0 M, suggesting that the Na+-specific binding to the negatively charged carboxyl triad causes a local conformational change around the binding site with an accompanying structural change in the overall protein, which contributes to the protein's structural destabilization. This spectroscopic evidence clarifies the molecular understanding of the inefficiency of salt to improve protein stability. The findings will inform the optimization of formulation conditions. |
| Databáze: | OpenAIRE |
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