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Measurement of Calcium Fluctuations Within the Sarcoplasmic Reticulum of Cultured Smooth Muscle Cells Using FRET-based Confocal Imaging
Published on: June 20, 2016
New ratiometric fluorescent calcium indicators with moderately attenuated binding affinities
K R Gee1, E A Archer, L A Lapham
1Molecular Probes, Inc., Eugene, OR 97402, USA. melodyouellet@probes.com
Bioorganic & Medicinal Chemistry Letters
|July 29, 2000
Summary
Researchers synthesized new halogenated calcium indicators, fura-2 and indo-1 derivatives, and novel benzothiaza probes. Halogenation position significantly impacted binding affinity, with new probes showing Kd values from 400 nM to 5.3 microM [Ca2+].
Area of Science:
- Chemical Synthesis
- Biophysical Chemistry
- Molecular Spectroscopy
Background:
- Calcium indicators are crucial for monitoring intracellular calcium dynamics.
- Modifying existing indicators can optimize their properties for specific applications.
- The BAPTA nucleus is a core component of many high-affinity calcium chelators.
Purpose of the Study:
- To synthesize and characterize mono-halogenated derivatives of fura-2 and indo-1 calcium indicators.
- To investigate the effect of halogenation position on the binding affinity of BAPTA-based indicators.
- To develop novel excitation ratioable fluorescent calcium indicators.
Main Methods:
- Synthesis of mono-halogenated fura-2 and indo-1 derivatives.
- Spectroscopic evaluation of synthesized compounds.
- Determination of dissociation constants (Kd) for calcium binding.
Main Results:
- Halogenation ortho or para to the bridging oxygen weakened binding affinity more than meta-position halogenation in fura derivatives.
- Two new excitation ratioable fluorescent calcium indicators, benzothiaza-1 and 2, were successfully synthesized.
- Observed Kd values for the new probes ranged from 400 nM to 5.3 microM [Ca2+].
Conclusions:
- The position of halogenation critically influences the calcium binding affinity of BAPTA derivatives.
- Novel benzothiaza indicators offer new tools for fluorescent calcium measurements.
- The synthesized probes exhibit a range of affinities suitable for diverse biological research.
