A New Protein Conformation Indicator Based on Biarsenical Fluorescein with an Extended Benzoic Acid Moiety

Jun Nakanishi, Mizuo Maeda, Yoshio Umezawa

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We demonstrate herein a new protein conformation indicator based on biarsenical fluorescein with an extended benzoic acid moiety. The present indicator is reactive to a genetically introduced tetracysteine motif (Cys-Cys-Xaa-Xaa-Cys-Cys, where Xaa is a noncysteine amino acid) of proteins. Compared to the original biarsenical fluorescein (FlAsH) and the biarsenical Nile red analogue (BArNile), the present indicator exhibited larger fluorescence intensity changes in response to Ca2+-induced conformational rearrangements of calmodulin. A calculation of the highest occupied molecular orbital (HOMO) level of the benzoic acid moiety of the indicator molecule supports possible involvement of a photoinduced electron transfer (PET) process. These results indicate that the present indicator is useful for sensitive detection of protein conformational changes.

Original languageEnglish
Pages (from-to)273-278
Number of pages6
JournalAnalytical Sciences
Issue number2
Publication statusPublished - 2004 Feb 1
Externally publishedYes


ASJC Scopus subject areas

  • Analytical Chemistry

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