Design and Synthesis of Mg2+-Selective Fluoroionophores Based on a Coumarin Derivative and Application for Mg2+ Measurement in a Living Cell
详细信息 查看全文
- 作者：Yoshio Suzuki ; Hirokazu Komatsu ; Takafumi Ikeda ; Naohiko Saito ; Sawa Araki ; Daniel Citterio ; Hideaki Hisamoto ; Yoshiichiro Kitamura ; Takeshi Kubota ; Jun Nakagawa ; Kotaro Oka ; and Koji Suzuki
- 刊名：Analytical Chemistry
- 出版年：2002
- 出版时间：March 15, 2002
- 年：2002
- 卷：74
- 期：6
- 页码：1423 - 1428
- 全文大小：322K
- 年卷期：v.74,no.6(March 15, 2002)
- ISSN：1520-6882
文摘
Novel Mg2+ fluorescent molecular probes (KMG-20-AMand KMG-27-AM; where AM is an acetoxymethyl group)based on a coumarin possessing a charged 
-diketonestructure were designed and synthesized. These fluorescent probes produced a red shift from 425 to 445 nm inthe absorption spectra after formation of a complex withMg2+. The fluorescence spectra of these probes alsoshowed a red shift from 485 to 495 nm and an increasingfluorescence intensity after formation of a complex withMg2+. The optimum experimental conditions were excitation wavelength of 445 nm and a monitored wavelengthof 500 nm, where these probes functioned as an indicatorshowing an image of increasing fluorescence in the presence of Mg2+. These probes showed a "seesaw-type"fluorescent spectral change with the isosbestic point at480 nm due to the light excitation at 445 nm, whichindicates that ratiometry can be used for the measurement. The molecular probes formed a 1:1 complex withMg2+ and the dissociation constant (Kd) was 10.0 mM forKMG-20. The association constants of the probes withMg2+ were ~3 times higher than that with Ca2+, whichshowed that the selectivity of Mg2+ versus Ca2+ for theseprobes was over 200 times higher than that for commercially available Mg2+ fluorescent molecular probessuch as mag-fura-2, Magnesium Green. As an applicationof these probes, intracellular fluorescent imaging of Mg2+was demonstrated using a fluorescent microscope. Afterthe addition of KMG-20-AM and KMG-27-AM into PC12cells, a strong fluorescence was observed in the cytoplasmand a weak fluorescence in the nuclei region. Aftertreatment with a high-K+ medium, the fluorescence intensity increased due to increasing intracellular Mg2+. Thereal image of Mg2+ release from the magnesium store wassuccessfully observed with these Mg2+ fluorescent probes.
-diketonestructure were designed and synthesized. These fluorescent probes produced a red shift from 425 to 445 nm inthe absorption spectra after formation of a complex withMg2+. The fluorescence spectra of these probes alsoshowed a red shift from 485 to 495 nm and an increasingfluorescence intensity after formation of a complex withMg2+. The optimum experimental conditions were excitation wavelength of 445 nm and a monitored wavelengthof 500 nm, where these probes functioned as an indicatorshowing an image of increasing fluorescence in the presence of Mg2+. These probes showed a "seesaw-type"fluorescent spectral change with the isosbestic point at480 nm due to the light excitation at 445 nm, whichindicates that ratiometry can be used for the measurement. The molecular probes formed a 1:1 complex withMg2+ and the dissociation constant (Kd) was 10.0 mM forKMG-20. The association constants of the probes withMg2+ were ~3 times higher than that with Ca2+, whichshowed that the selectivity of Mg2+ versus Ca2+ for theseprobes was over 200 times higher than that for commercially available Mg2+ fluorescent molecular probessuch as mag-fura-2, Magnesium Green. As an applicationof these probes, intracellular fluorescent imaging of Mg2+was demonstrated using a fluorescent microscope. Afterthe addition of KMG-20-AM and KMG-27-AM into PC12cells, a strong fluorescence was observed in the cytoplasmand a weak fluorescence in the nuclei region. Aftertreatment with a high-K+ medium, the fluorescence intensity increased due to increasing intracellular Mg2+. Thereal image of Mg2+ release from the magnesium store wassuccessfully observed with these Mg2+ fluorescent probes.