1
|
Archipowa N, Wittmann L, Köckenberger J, Ertl FJ, Gleixner J, Keller M, Heinrich MR, Kutta RJ. Characterization of Fluorescent Dyes Frequently Used for Bioimaging: Photophysics and Photocatalytical Reactions with Proteins. J Phys Chem B 2023; 127:9532-9542. [PMID: 37903729 DOI: 10.1021/acs.jpcb.3c04484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
Derivatives of the rhodamine-based dye 5-TAMRA (5-carboxy-tetramethylrhodamine) and the indocarbocyanine-type Cy3B (cyclized derivative of the cyanine dye Cy3), both representing important fluorophores frequently used for the labeling of biomolecules (proteins, nucleic acids) and bioactive compounds, such as receptor ligands, were photophysically investigated in aqueous solution, i.e., in neat phosphate-buffered saline (PBS) and in PBS supplemented with 1 wt % bovine serum albumin (BSA). The dyes exhibit comparable absorption (λabs,max: 550-569 nm) and emission wavelengths (λem,max: 580-582 nm), and similar S1 lifetimes (2.27-2.75 ns), and their excited state deactivation proceeds mainly via the lowest excited singlet state (triplet quantum yield ca. 1%). However, the probes show marked differences with respect to their fluorescence quantum yield and photostability. While 5-TAMRA shows a lower quantum yield (37-39%) than the Cy3B derivative (ca. 57%), its photostability is considerably higher compared to Cy3B. Generally, the impact of the protein on the photophysics is low. However, on prolonged illumination, both fluorescent dyes undergo a photocatalytic reaction with tryptophan residues of BSA mediated by sensitized singlet oxygen resulting in a tryptophan photoproduct with an absorption maximum around 330 nm. The overall results of this work will assist in choosing the right dye for the labeling of bioactive compounds, and the study demonstrates that experiments performed with 5-TAMRA or Cy3B-labeled compounds in a biological environment may be influenced by photochemical modification of experimentally relevant proteins at aromatic amino acid residues.
Collapse
Affiliation(s)
- Nataliya Archipowa
- Institute of Biophysics and Physical Biochemistry, Faculty of Biology and Preclinical Medicine, University of Regensburg, D-93053 Regensburg, Germany
| | - Lukas Wittmann
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Johannes Köckenberger
- Department of Chemistry and Pharmacy, Molecular and Clinical Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, D-91058 Erlangen, Germany
| | - Fabian J Ertl
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Jakob Gleixner
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Max Keller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Markus R Heinrich
- Department of Chemistry and Pharmacy, Molecular and Clinical Pharmacy, Friedrich-Alexander-University Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, D-91058 Erlangen, Germany
| | - Roger Jan Kutta
- Institute of Physical and Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| |
Collapse
|
2
|
Konieczny A, Conrad M, Ertl FJ, Gleixner J, Gattor AO, Grätz L, Schmidt MF, Neu E, Horn AHC, Wifling D, Gmeiner P, Clark T, Sticht H, Keller M. N-Terminus to Arginine Side-Chain Cyclization of Linear Peptidic Neuropeptide Y Y 4 Receptor Ligands Results in Picomolar Binding Constants. J Med Chem 2021; 64:16746-16769. [PMID: 34748345 DOI: 10.1021/acs.jmedchem.1c01574] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The family of neuropeptide Y (NPY) receptors comprises four subtypes (Y1R, Y2R, Y4R, Y5R), which are addressed by at least three endogenous peptides, i.e., NPY, peptide YY, and pancreatic polypeptide (PP), the latter showing a preference for Y4R. A series of cyclic oligopeptidic Y4R ligands were prepared by applying a novel approach, i.e., N-terminus to arginine side-chain cyclization. Most peptides acted as Y4R partial agonists, showing up to 60-fold higher Y4R affinity compared to the linear precursor peptides. Two cyclic hexapeptides (18, 24) showed higher Y4R potency (Ca2+ aequorin assay) and, with pKi values >10, also higher Y4R affinity compared to human pancreatic polypeptide (hPP). Compounds such as 18 and 24, exhibiting considerably lower molecular weight and considerably more pronounced Y4R selectivity than PP and previously described dimeric peptidic ligands with high Y4R affinity, represent promising leads for the preparation of labeled tool compounds and might support the development of drug-like Y4R ligands.
Collapse
Affiliation(s)
- Adam Konieczny
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Marcus Conrad
- Institute of Biochemistry, Emil-Fischer-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Fahrstraße 17, D-91054 Erlangen, Germany
| | - Fabian J Ertl
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Jakob Gleixner
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Albert O Gattor
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Lukas Grätz
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Maximilian F Schmidt
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, D-91058 Erlangen, Germany
| | - Eduard Neu
- Department of Chemistry and Pharmacy, Computer-Chemistry-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Nägelsbachstraße 25, D-91052 Erlangen, Germany
| | - Anselm H C Horn
- Institute of Biochemistry, Emil-Fischer-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Fahrstraße 17, D-91054 Erlangen, Germany
| | - David Wifling
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, D-91058 Erlangen, Germany
| | - Timothy Clark
- Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-University Erlangen-Nürnberg, Nikolaus-Fiebiger-Straße 10, D-91058 Erlangen, Germany.,Department of Chemistry and Pharmacy, Computer-Chemistry-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Nägelsbachstraße 25, D-91052 Erlangen, Germany
| | - Heinrich Sticht
- Institute of Biochemistry, Emil-Fischer-Center, Friedrich-Alexander-University Erlangen-Nürnberg, Fahrstraße 17, D-91054 Erlangen, Germany
| | - Max Keller
- Institute of Pharmacy, Faculty of Chemistry and Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| |
Collapse
|