Analysis of the role of Mg²⁺ on conformational change and target recognition by Ciliate Euplotes octocarinatus centrin

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• 作者：Yaqin Zhao^a ;   ; ^b ;   ; ^c ; Jun Yan^b ;   ; ^c ; Yanan Feng^b ;   ; ^c ; Aihua Liang^a ;   ; ^c ;   ; ^{aliang@sxu.edu.cn} ; Binsheng Yang^b ;   ; ^c ;   ; ^{yangbs@sxu.edu.cn}
• 关键词：Centrin ; Magnesium ; Melittin ; Conformational change
• 刊名：Journal of Photochemistry and Photobiology B: Biology
• 出版年：2011
• 出版时间：5 October 2011
• 年：2011
• 卷：105
• 期：1
• 页码：60-68
• 全文大小：501 K

文摘

The binding of Mg²⁺ with the Euplotes octocarinatus centrin (EoCen) and the effect of Mg²⁺ on the binding of EoCen with the peptide melittin were examined by spectroscopic methods. In this study, it was found that Mg²⁺ may bind with Ca²⁺-binding sites, at least partly, on EoCen, which displays ?0-fold weaker affinity than Ca²⁺. In the presence of Mg²⁺, Ca²⁺-saturated EoCen undergoes significant conformational changes resulting in decreased exposure of hydrophobic surfaces on the protein. Additionally, excess Mg²⁺ did not change the stoichiometry, but rather reduced the affinity of EoCen to melittin. The Mg²⁺-dependent decrease in the affinities of EoCen to melittin is an intrinsic property of Mg²⁺, rather than a nonspecific ionic effect. The inhibitory effect of Mg²⁺ on the formation of complexes between EoCen and melittin may contribute to the specificity of EoCen in target activation in response to cellular Ca²⁺ concentration fluctuations.