Ion specific influences on the stability and unfolding transitions of a naturally aggregating protein; RecA

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• 作者：William R. Cannon^a ; ¹ ; Nathaniel D. Talley^a ; ¹ ; Brittany A. Danzig^a ; Xiaomei Liu^b ; Jennifer S. Martinez^b ; Andrew P. Shreve^b ; ^c ; Gina MacDonald^a ; ^{macdongx@jmu.edu}
• 关键词：CD ; Circular Dichroism ; Tris ; tris(hydroxymethyl)aminoethane ; MANT ; 2&prime ; -3&prime ; O-(N-methylanthraniloyl) ; DLS ; Dynamic Light Scattering
• 刊名：Biophysical Chemistry
• 出版年：2012
• 期刊代码：11_03014622
• 类别：ch
• 出版时间：April, 2012
• 卷：163-164
• 期：Complete
• 页码：56-63
• 文件大小：844 K

摘要

The Escherichia coli RecA protein is a naturally aggregated protein complex that is affected by the presence of salts. In order to gain further insight into the nature of the ion-interactions on a naturally aggregating protein we used circular dichroism (CD), fluorescence and dynamic light scattering (DLS) to study the effects of different concentrations of MgCl₂, CaCl₂, NaCl, Na₂SO₄, and MgSO₄ on RecA structure and thermal unfolding. The results show unique ion influences on RecA structure, aggregation, unfolding transitions and stability and the anion effects correlate with the reverse Hofmeister series. The mechanisms of the ion-induced changes most likely result from specific ion binding, changes in the interfacial tension and altered protein-solvent interactions that may be especially important for protein-protein interactions in naturally aggregating proteins. The presence of some ions leads to the formation of RecA complexes that are resistant to complete denaturation and nonspecific aggregation.