A directly linked pyrene–dimethylaniline derivative as a potential biochemical sensor for the microenvironmental dielectric properties of the active site of enzymes

Abstract

Permittivity is a very important physical parameter for a detailed understanding of interactions in a biological system. However, at the moment no common experimental method is available for measuring the dielectric constants of a microenvironment or on a local level, and one has to rely on theoretical simulations. In this work we can demonstrate that it is experimentally possible to estimate the dielectric constant of the active site of the enzyme acetylcholinesterase, based on the spectroscopic properties of the laser dye N,N-dimethyl(4-pyren-1ylphenyl)amine. It was found that the dye specifically attaches to the active site of acetylcholinesterase and therefore inhibits its functionality. The microenvironmental dielectric properties, which are spectroscopically sensed, and enzymatic functionality can be combined and might potentially be developed to a biosensing element.

Aspects of the Photodimerization Mechanism of 2,4-Dichlorocinnamic Acid Studied by Kinetic Photocrystallography

“…[1][2][3] In synthetic chemistry, template-controlled reactions in the organic solid state can be used to construct a molecule that functions as an organic building unit of both a metal-organic polyhedron and polygon. 4 In this way, it is possible to simulate two-step processes which consist of a template-directed synthesis step and a self-assembly step in order to construct large, functional self-assembled structures.…”

Determination of the Relative Permittivity of Acetylcholinesterase

“…As discussed in our previous work, PyDMA in complex with AChE has an emission maximum at 22176 cm −1 (450 nm), indicating a dielectric constant of 3.72 ± 0.33 for the PyDMA binding region. Since PyDMA is a competitive inhibitor for AChE, we can conclude that the determined relative permittivity corresponds to the active site/gorge region. The low relative permittivity value is comparable to that of benzene (relative permittivity = 2.3).…”

“…That is the case for the fluorophore tryptophan and dyes like the intramolecular electron donor/ electron acceptor compound N,N-dimethyl(4-pyren-1-phenyl)amine, PyDMA. [3][4][5][6] The stronger the solute/solvent interaction, the bigger the Gibbs free energy of the solvation of the excited state, and the larger the red shift of the emission band of the fluorophore and the corresponding Stokes shift.…”

“…When the dipole moment of a fluorescent molecule is larger in the excited state than that in the ground state, the extent of solvation of the excited state strongly depends on the polarity of the varying solvent and increases the fluorescence in the Stokes shift with increasing solvent polarity. That is the case for the fluorophore tryptophan and dyes like the intramolecular electron donor/electron acceptor compound N , N -dimethyl(4-pyren-1-phenyl)amine, PyDMA. − The stronger the solute/solvent interaction, the bigger the Gibbs free energy of the solvation of the excited state, and the larger the red shift of the emission band of the fluorophore and the corresponding Stokes shift.…”

A Pyrene- and Phosphonate-Containing Fluorescent Probe as Guest Molecule in a Host Polymer Matrix

“…Moreover, no example describing a pyrene derivative used as sensor for solid materials has been previously reported. Pyrene-based sensors are only used in solution for the determination of domains in complex biological systems, such as biological polymers [ 26 , 27 ] and in enzymes [ 28 ]. In these cases, the sensor is designed in order to form electrostatic interactions (presence of a cationic motif) and/or hydrophobic interactions (presence of fluorescent pyrene motif and/or alkyl chains) with the biological system.…”