Synthesis and properties of Asante Calcium Red—A novel family of long excitation wavelength calcium indicators
| Autor: | Mark P. Goldberg, Patrick P.L. Chan, Akwasi Minta, Xenia Meshik, Krzysztof L. Hyrc, P. Rogelio Escamilla |
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| Rok vydání: | 2013 |
| Předmět: |
Light
Physiology Green Fluorescent Proteins Analytical chemistry chemistry.chemical_element Calcium Heterocyclic Compounds 4 or More Rings Article Rats Sprague-Dawley Mice chemistry.chemical_compound BAPTA Animals Humans Chelation Emission spectrum Molecular Biology Magnesium ion Fluorescent Dyes Ions Neurons Aniline Compounds Microscopy Confocal Cell Biology Hydrogen-Ion Concentration Fluorescence Rats Dissociation constant HEK293 Cells Spectrometry Fluorescence chemistry Calibration Indicators and Reagents Visible spectrum |
| Zdroj: | Cell Calcium. 54:320-333 |
| ISSN: | 0143-4160 |
| DOI: | 10.1016/j.ceca.2013.08.001 |
| Popis: | Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450-540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca(2+)-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (< 490 nm) or multiphoton (∼780 nm) excitation. Therefore, both probes can be used as single wavelength or, less dynamic, ratiometric indicators. Long indicator emission might allow easy [Ca2+]i measurement in GFP expressing cells. The indicators bind Ca2+ with either high (Kd = 0.49 ± 0.07 μM; ACR-1) or low affinity (Kd = 6.65 ± 0.13 μM; ACR-1-LA). Chelating Zn2+ (Kd = 0.38 ± 0.02 nM) or Mg2+ (Kd∼5mM) slightly raises and binding Co2+ quenches dye fluorescence. New indicators are somewhat pH-sensitive (pKa = 6.31 ± 0.07), but fairly resistant to bleaching. The probes are rather dim, which combined with low AM ester loading efficiency, might complicate in situ imaging. Despite potential drawbacks, ACR-1 and ACR-1-LA are promising new calcium indicators. |
| Databáze: | OpenAIRE |
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