Amine-Reactive BODIPY Dye: Spectral Properties and Application for Protein Labeling

Abstract

A boron-dipyrromethene (BODIPY) derivative reactive towards amino groups of proteins (NHS-Ph-BODIPY) was synthesized. Spectroscopic and photophysical properties of amine-reactive NHS-Ph-BODIPY and its non-reactive precursor (COOH-Ph-BODIPY) in a number of organic solvents were investigated. Both fluorescent dyes were characterized by green absorption (521–532 nm) and fluorescence (538–552 nm) and medium molar absorption coefficients (46,500–118,500 M−1·cm−1) and fluorescence quantum yields (0.32 – 0.73). Solvent polarizability and dipolarity were found to play a crucial role in solvent effects on COOH-Ph-BODIPY and NHS-Ph-BODIPY absorption and emission bands maxima. Quantum-chemical calculations were used to show why solvent polarizability and dipolarity are important as well as to understand how the nature of the substituent affects spectroscopic properties of the fluorescent dyes. NHS-Ph-BODIPY was used for fluorescent labeling of a number of proteins. Conjugation of NHS-Ph-BODIPY with bovine serum albumin (BSA) resulted in bathochromic shifts of absorption and emission bands and noticeable fluorescence quenching (about 1.5 times). It was demonstrated that the sensitivity of BSA detection with NHS-Ph-BODIPY was up to eight times higher than with Coomassie brilliant blue while the sensitivity of PII-like protein PotN (PotN) detection with NHS-Ph-BODIPY and Coomassie brilliant blue was almost the same. On the basis of the molecular docking results, the most probable binding sites of NHS-Ph-BODIPY in BSA and PotN and the corresponding binding free energies were estimated.

Ultrashort Peptide Grafting on Mesoporous Films and Its Impact on Ionic Mesopore Accessibility

“…As no change in the fluorescence intensity was observed, the different fluorescence spectra were ascribed to the arginine grafting. The fluorescence wavelength and intensity change upon peptide grafting to BODIPY are in agreement with the literature as the peptide binding affects HOMO and LUMO energy levels. , Thus, the observed fluorescence intensity changes upon amino acid grafting as well as supports the successful grafting of amino acid into the BODIPY-functionalized silica mesopores. Thereby, the macroscopic static contact angle of all samples remains hydrophilic between 58 and 38° (Figure S9).…”

BODIPY(aryl)iodonium salts in the efficient synthesis of diversely functionalized BODIPYs and selective detection of serum albumin

“…38 The extremely versatile BODIPY derivatives exhibit excellent photophysical properties like red-shifted UV-Visible absorption maxima, high molar absorption coefficients (ε), broad emission bandwidths, large Stokes shifts and high fluorescence quantum yields as well as high photo-stability. 39 Due to these advantageous features, BODIPY and derived compounds are used for biochemical labelling, 40,41 light-emitting devices, 42 and light harvesting systems, 43 and as sensitizers in solar cells. 44 Since serum albumin is the most abundantly present plasma protein and binds to diverse groups of drugs, hormones, enzymes etc., it is frequently used as a model protein to study the interaction with small molecules using fluorescence spectroscopy.…”

Fluorescence Labeling of Peptides: Finding the Optimal Protocol for Coupling Various Dyes to ATCUN-like Structures

“…Notably, cyclization of FAM has also been reported; however, the pH window under which FAM is in the open, fluorescent form is between 6 and 9, enhancing its applicability in biological assays. , 4,4-Difluoro-4-bora-3a,4a-diaza- s -indacene (BODIPY) being another widely applied fluorescent core has also found application in many different fields . Due to their generally relatively sharp fluorescence peaks, high quantum yields, and additional insensitivity to pH and other environmental conditions, prematurely, they have found great application in biological studies and are widely used to label peptides and proteins. − For our application, the BODIPY core can be modified to carry a carboxylic acid on one of its pyrrole functionalities, giving rise to BODIPY-FL-propanoic acid (Figure a), , which can be directly applied for amide bond formation in peptide synthesis.…”