Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin
Heteroprotein complex coacervation is an assembly formed by oppositely charged proteins in aqueous solution that leads to liquid–liquid phase separation. The ability of lactoferrin and β-lactoglobulin to form complex coacervates at pH 5.5 under optimal protein stoichiometry has been studied in a pre...
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MDPI AG
2023-03-01
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| Series: | Foods |
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| Online Access: | https://www.mdpi.com/2304-8158/12/5/1040 |
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| author | Rima Soussi Hachfi Pascaline Hamon Florence Rousseau Marie-Hélène Famelart Saïd Bouhallab |
| author_facet | Rima Soussi Hachfi Pascaline Hamon Florence Rousseau Marie-Hélène Famelart Saïd Bouhallab |
| author_sort | Rima Soussi Hachfi |
| collection | DOAJ |
| description | Heteroprotein complex coacervation is an assembly formed by oppositely charged proteins in aqueous solution that leads to liquid–liquid phase separation. The ability of lactoferrin and β-lactoglobulin to form complex coacervates at pH 5.5 under optimal protein stoichiometry has been studied in a previous work. The goal of the current study is to determine the influence of ionic strength on the complex coacervation between these two proteins using direct mixing and desalting protocols. The initial interaction between lactoferrin and β-lactoglobulin and subsequent coacervation process were highly sensitive to the ionic strength. No microscopic phase separation was observed beyond a salt concentration of 20 mM. The coacervate yield decreased drastically with increasing added NaCl from 0 to 60 mM. The charge-screening effect induced by increasing the ionic strength is attributed to a decrease of interaction between the two oppositely charged proteins throughout a decrease in Debye length. Interestingly, as shown by isothermal titration calorimetry, a small concentration of NaCl around 2.5 mM promoted the binding energy between the two proteins. These results shed new light on the electrostatically driven mechanism governing the complex coacervation in heteroprotein systems. |
| first_indexed | 2024-03-11T07:24:13Z |
| format | Article |
| id | doaj.art-191291c6f278440ab0003201d2a8cc63 |
| institution | Directory Open Access Journal |
| issn | 2304-8158 |
| language | English |
| last_indexed | 2024-03-11T07:24:13Z |
| publishDate | 2023-03-01 |
| publisher | MDPI AG |
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| series | Foods |
| spelling | doaj.art-191291c6f278440ab0003201d2a8cc632023-11-17T07:41:28ZengMDPI AGFoods2304-81582023-03-01125104010.3390/foods12051040Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-LactoglobulinRima Soussi Hachfi0Pascaline Hamon1Florence Rousseau2Marie-Hélène Famelart3Saïd Bouhallab4INRAE, Institut Agro, STLO, 65 Rue de Saint Brieuc, F-35042 Rennes, FranceINRAE, Institut Agro, STLO, 65 Rue de Saint Brieuc, F-35042 Rennes, FranceINRAE, Institut Agro, STLO, 65 Rue de Saint Brieuc, F-35042 Rennes, FranceINRAE, Institut Agro, STLO, 65 Rue de Saint Brieuc, F-35042 Rennes, FranceINRAE, Institut Agro, STLO, 65 Rue de Saint Brieuc, F-35042 Rennes, FranceHeteroprotein complex coacervation is an assembly formed by oppositely charged proteins in aqueous solution that leads to liquid–liquid phase separation. The ability of lactoferrin and β-lactoglobulin to form complex coacervates at pH 5.5 under optimal protein stoichiometry has been studied in a previous work. The goal of the current study is to determine the influence of ionic strength on the complex coacervation between these two proteins using direct mixing and desalting protocols. The initial interaction between lactoferrin and β-lactoglobulin and subsequent coacervation process were highly sensitive to the ionic strength. No microscopic phase separation was observed beyond a salt concentration of 20 mM. The coacervate yield decreased drastically with increasing added NaCl from 0 to 60 mM. The charge-screening effect induced by increasing the ionic strength is attributed to a decrease of interaction between the two oppositely charged proteins throughout a decrease in Debye length. Interestingly, as shown by isothermal titration calorimetry, a small concentration of NaCl around 2.5 mM promoted the binding energy between the two proteins. These results shed new light on the electrostatically driven mechanism governing the complex coacervation in heteroprotein systems.https://www.mdpi.com/2304-8158/12/5/1040complex coacervationionic strengthproteinsdesalting |
| spellingShingle | Rima Soussi Hachfi Pascaline Hamon Florence Rousseau Marie-Hélène Famelart Saïd Bouhallab Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin Foods complex coacervation ionic strength proteins desalting |
| title | Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin |
| title_full | Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin |
| title_fullStr | Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin |
| title_full_unstemmed | Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin |
| title_short | Ionic Strength Dependence of the Complex Coacervation between Lactoferrin and β-Lactoglobulin |
| title_sort | ionic strength dependence of the complex coacervation between lactoferrin and β lactoglobulin |
| topic | complex coacervation ionic strength proteins desalting |
| url | https://www.mdpi.com/2304-8158/12/5/1040 |
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