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A specific fluorescent probe reveals compromised activity of methionine sulfoxide reductases in Parkinson's disease † † Electronic supplementary information (ESI) available: The characterization of probes, experimental procedures, supporting data and original spectra ( 1 H NMR, 13 C NMR, and MS) of the final 23 compounds. See DOI: 10.1039/c6sc04708d Click here for additional data file.

View Article: PubMed Central - PubMed

ABSTRACT

Oxidation of methionine residues to methionine sulfoxide (MetSO) may cause changes in protein structure and function, and may eventually lead to cell damage. Methionine sulfoxide reductases (Msrs) are the only known enzymes that catalyze the reduction of MetSO back to methionine by taking reducing equivalents from the thioredoxin system, and thus protect cells from oxidative damage. Nonetheless, a lack of convenient assays for the enzymes hampers the exploration of their functions. We report the discovery of Msr-blue, the first turn-on fluorescent probe for Msr with a >100-fold fluorescence increment from screening a rationally-designed small library. Intensive studies demonstrated the specific reduction of Msr-blue by the enzymes. Msr-blue is ready to determine Msr activity in biological samples and live cells. Importantly, we disclosed a decline of Msr activity in a Parkinson's model, thus providing a mechanistic linkage between the loss of function of Msrs and the development of neurodegeneration. The strategy for the discovery of Msr-blue would also provide guidance for developing novel probes with longer excitation/emission wavelengths and specific probes for Msr isoforms.

No MeSH data available.


The sulfoxides library.
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fig1: The sulfoxides library.

Mentions: We created a focused small library containing 23 dyes uniformly decorated with a methyl sulfoxide group (1–23, Fig. 1), and evaluated their reduction by Msr. The synthetic routes are illustrated in the ESI† (Schemes S1–3). Characterizations and the original spectra (1H NMR, 13C NMR, and MS) of the final compounds are included in the ESI† (Fig. S4–71). Compound 15 (Msr-blue) was identified as the first turn-on fluorescent probe for Msr with a more than 100-fold fluorescence increment. The specific activation of Msr-blue by Msr was further demonstrated. Msr-blue is ready to image enzyme function in live cells and to measure enzyme activity in biological samples. With the aid of Msr-blue, a decline in enzyme activity in a cellular model of Parkinson's disease (PD) was disclosed for the first time. We expect the probe would facilitate an understanding of the physiological/pathophysiological functions of Msrs. In addition, the concept of the probe design would also advance the development of novel Msr probes with longer excitation/emission wavelengths as well as specific Msr A and Msr B probes.


A specific fluorescent probe reveals compromised activity of methionine sulfoxide reductases in Parkinson's disease † † Electronic supplementary information (ESI) available: The characterization of probes, experimental procedures, supporting data and original spectra ( 1 H NMR, 13 C NMR, and MS) of the final 23 compounds. See DOI: 10.1039/c6sc04708d Click here for additional data file.
The sulfoxides library.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382841&req=5

fig1: The sulfoxides library.
Mentions: We created a focused small library containing 23 dyes uniformly decorated with a methyl sulfoxide group (1–23, Fig. 1), and evaluated their reduction by Msr. The synthetic routes are illustrated in the ESI† (Schemes S1–3). Characterizations and the original spectra (1H NMR, 13C NMR, and MS) of the final compounds are included in the ESI† (Fig. S4–71). Compound 15 (Msr-blue) was identified as the first turn-on fluorescent probe for Msr with a more than 100-fold fluorescence increment. The specific activation of Msr-blue by Msr was further demonstrated. Msr-blue is ready to image enzyme function in live cells and to measure enzyme activity in biological samples. With the aid of Msr-blue, a decline in enzyme activity in a cellular model of Parkinson's disease (PD) was disclosed for the first time. We expect the probe would facilitate an understanding of the physiological/pathophysiological functions of Msrs. In addition, the concept of the probe design would also advance the development of novel Msr probes with longer excitation/emission wavelengths as well as specific Msr A and Msr B probes.

View Article: PubMed Central - PubMed

ABSTRACT

Oxidation of methionine residues to methionine sulfoxide (MetSO) may cause changes in protein structure and function, and may eventually lead to cell damage. Methionine sulfoxide reductases (Msrs) are the only known enzymes that catalyze the reduction of MetSO back to methionine by taking reducing equivalents from the thioredoxin system, and thus protect cells from oxidative damage. Nonetheless, a lack of convenient assays for the enzymes hampers the exploration of their functions. We report the discovery of Msr-blue, the first turn-on fluorescent probe for Msr with a >100-fold fluorescence increment from screening a rationally-designed small library. Intensive studies demonstrated the specific reduction of Msr-blue by the enzymes. Msr-blue is ready to determine Msr activity in biological samples and live cells. Importantly, we disclosed a decline of Msr activity in a Parkinson's model, thus providing a mechanistic linkage between the loss of function of Msrs and the development of neurodegeneration. The strategy for the discovery of Msr-blue would also provide guidance for developing novel probes with longer excitation/emission wavelengths and specific probes for Msr isoforms.

No MeSH data available.