Publications by authors named "Tara Vohs"

2 Publications

  • Page 1 of 1

Ratiometric Detection of Glutathione Based on Disulfide Linkage Rupture between a FRET Coumarin Donor and a Rhodamine Acceptor.

Chembiochem 2021 May 13. Epub 2021 May 13.

Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA.

Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor. Under the excitation of the coumarin donor at 405 nm, the probe shows weak visible fluorescence of the coumarin donor at 470 nm and strong near-infrared fluorescence of the rhodamine acceptor at 652 nm due to efficient Forster resonance energy transfer (FRET) from the donor to the acceptor. Glutathione breaks the disulfide bond through reduction, which results in a dramatic increase in coumarin fluorescence and a corresponding decrease in rhodamine fluorescence. The probe possesses excellent cell permeability, biocompatibility, and good ratiometric fluorescence responses to glutathione and cysteine with a self-calibration capability. The probe was utilized to ratiometrically visualize glutathione concentration alterations in HeLa cells and Drosophila melanogaster larvae.
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http://dx.doi.org/10.1002/cbic.202100108DOI Listing
May 2021

Ratiometric Near-Infrared Fluorescent Probes Based on Hemicyanine Dyes Bearing Dithioacetal and Formal Residues for pH Detection in Mitochondria.

Molecules 2021 Apr 6;26(7). Epub 2021 Apr 6.

Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA.

Ratiometric near-infrared fluorescent probes ( and ) have been prepared for pH determination in mitochondria by attaching dithioacetal and formal residues onto a hemicyanine dye. The reactive formyl group on probe allows for retention inside mitochondria as it can react with a protein primary amine residue to form an imine under slightly basic pH 8.0. Probes and display ratiometric fluorescent responses to pH changes through the protonation and deprotonaton of a hydroxy group in hemicyanine dyes with experimentally determined pa values of 6.85 and 6.49, respectively. Calculated p values from a variety of theoretical methods indicated that the SMD method of accounting for solvent and van der Waals radii plus including a water molecule located near the site of protonation produced the closest overall agreement with the experimental values at 7.33 and 6.14 for and respectively.
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http://dx.doi.org/10.3390/molecules26072088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8038704PMC
April 2021