Anisotropy and lifetime decay of green fluorescent protein in glycerol
Author
Brauner, MarenDate
2019Abstract
Fluorescence is a phenomena that can be observed on the surface of tonic water in sunlight, perceiving the emission of blue light from a substance called
quinine. In 1845 Sir John F. W. Herschel [1] discovered the previous phenomena. Nowadays, fluorescence embodies a useful research tool in various
scientific fields such as biology, not only acting as a stain for diverse applications such as tracing cell organelles but also giving presumably important
information about its environment such as the viscosity of the medium. This
work is focused on the green fluorescent protein (GFP) with the objective to
measure its emission spectra, its lifetime and anisotropy decay. According to
the executed experiment, the result for the emission peak is, located in the
green wavelength range at λem = 510 nm. The lifetime decay also shows
the expected behavior, involving the effects that occur during the excitation
period. For the anisotropy decay measurements, the objective is to compare
the measuring results with different models for the three dimensional shape
of the GFP. Knowing a term called rotational correlation time θ from the experiment, the volume V of the protein can be determined. If the volume is
defined and θ is measured, the viscosity of the medium that surrounds the
GFP can be found. This part of the research was complicated as not all of the
obtained data followed the expectations, hence, both models and ideas how
to improve the procedure will be discussed theoretically in more detail.