Revealing properties of the KfrA plasmid protein via combined DLS, AFM and electrokinetic measurements

Zbigniew Adamczyk , Marta Kujda , Małgorzata Nattich-Rak , Marta Ludwiczak , Grażyna Jagura-Burdzy , Małgorzata Adamczyk

Abstract

Physicochemical characteristics of the plasmid KfrA protein in electrolyte solutions were done using a combination of dynamic light scattering (DLS), atomic force microscopy (AFM) and electrokinetic methods. The size of the protein was determined via the diffusion coefficient measurements using DLS. It was revealed from these measurements that the protein exists in an aggregated state composed of four molecules. The size of the protein was also precisely determined via AFM imaging of single molecules adsorbed on mica from dilute solutions at pH =3.5. It was 10.6 nm in accordance with the value predicted for an aggregate composed of four monomers in a hexagonal configuration. The aggregation number was also confirmed by kinetics measurements carried out under diffusion controlled transport using AFM imaging of proteins. Further characteristics were acquired via KfrA adsorption on polystyrene latex particles (average size of 820 nm). The electrophoretic mobility of the latex and its zeta potential were determined as a function of the coverage of the protein. The maximum monolayer coverage for pH = 3.5 was 1.2 mg m−2. Additionally, from these measurements the effective charge of KfrA tetramer equal to 12e (elementary charges) was predicted. The KfrA monolayer on latex was used to determine the isoelectric point of the protein, which was pH = 4.5. As concluded, the procedures used in our work proved advantageous for a direct determination of aggregation processes and the effective charge if minor amounts of a protein are available.
Author Zbigniew Adamczyk - [Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences]
Zbigniew Adamczyk,,
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, Marta Kujda - [Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences]
Marta Kujda,,
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, Małgorzata Nattich-Rak - [Institute of Catalysis and Surface Chemistry of the Polish Academy of Sciences]
Małgorzata Nattich-Rak,,
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, Marta Ludwiczak - [Institute of Biochemistry and Biophysics of the Polish Academy of Sciences]
Marta Ludwiczak,,
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, Grażyna Jagura-Burdzy - [Institute of Biochemistry and Biophysics of the Polish Academy of Sciences]
Grażyna Jagura-Burdzy,,
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, Małgorzata Adamczyk (FC / IBC / DDTB)
Małgorzata Adamczyk,,
- Department Of Drug Technology And Biotechnology
Journal seriesColloids and Surfaces B-Biointerfaces, ISSN 0927-7765
Issue year2013
Vol103
Pages635-641
Publication size in sheets0.5
Keywords in EnglishAFM measurements of plasmid protein adsorption, KfrA plasmid protein adsorption, KfrA plasmid protein properties, Latex covered by KfrA plasmid protein
ASJC Classification1505 Colloid and Surface Chemistry; 1606 Physical and Theoretical Chemistry; 3110 Surfaces and Interfaces; 2700 General Medicine; 1305 Biotechnology
DOIDOI:10.1016/j.colsurfb.2012.10.065
URL http://www.sciencedirect.com/science/article/pii/S0927776512006388
Languageen angielski
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1-s2.0-S0927776512006388-main.pdf 469.12 KB
Score (nominal)35
Score sourcejournalList
ScoreMinisterial score = 30.0, 02-02-2020, ArticleFromJournal
Ministerial score (2013-2016) = 35.0, 02-02-2020, ArticleFromJournal
Publication indicators Scopus Citations = 8; WoS Citations = 7; Scopus SNIP (Source Normalised Impact per Paper): 2013 = 1.573; WoS Impact Factor: 2013 = 4.287 (2) - 2013=4.226 (5)
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