Mechanisms of Quenching of Alexa Fluorophores by Natural Amino Acids

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• 作者：Huimin Chen ; Syed S. Ahsan ; Mitk’ ; El B. Santiago-Berrios ; Hector D. Abrua ; Watt W. Webb
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：June 2, 2010
• 年：2010
• 卷：132
• 期：21
• 页码：7244-7245
• 全文大小：130K
• 年卷期：v.132,no.21(June 2, 2010)
• ISSN：1520-5126

文摘

Quenching of fluorophores by the same proteins that they covalently label is a phenomenon that is neither well-known nor well-characterized. It is often assumed that fluorophores are unperturbed by their target proteins. However, it has been observed that attached fluorophores can be quenched by contact with amino acids within the same protein, and this property has been exploited to report on changing conformational states or intramolecular dynamics of proteins. We show in this communication that fluorescence of Alexa dyes is, in fact, quenched by interactions with Trp, Tyr, Met, and His residues through a combination of static and dynamic quenching mechanisms. In light of this finding, the potential effect of intramolecular quenching should be considered in the interpretation of data that involves quantitative measurements of fluorescence intensity in proteins.