A new protein conformation indicator based on biarsenical fluorescein with an extended benzoic acid moiety.
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 Ca(2+)-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.
Nakanishi
Jun
J
Bioengineering Laboratory, RIKEN, Hirosawa, Wako 351-0198, Japan.
Maeda
Mizuo
M
Umezawa
Yoshio
Y
D019817:Benzoic Acid / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D019793:Fluorescein / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D011487:Protein Conformation
D005456:Fluorescent Dyes; D019817:Benzoic Acid; D019793:Fluorescein