Protein Folding

Idea: in this experiment we investigate protein (un)folding
by chemical denaturation of human serum albumin using tryptophan as an intrinsic fluorescent reporter

Biophysics Lab Course, Institute of Biophysics, Ulm University


The folding equilibrium of the plasmaprotein HSA (Human Serum Albumin) is characterized from the fluorescence of a tryptophan residue at position 214.

Successive addition of the denaturant GdmCl leads to an increasing spectral shift of Trp-214 fluorescence, which allows to quantify the increasing fraction of unfolded protein.

The free energy change between folded and unfolded state is determined for two different pH-values by extrapolation to zero denaturant concentration.