Fluorescence

[Bhupesh Taneja]

Hi all!
1)      I want to do folding-unfolding studies with my protein.
Unfortuantely, the single tryptophan is partially exposed. (as from
homologous xtal strucures and by quenching with KI). The emission maxima
I obtain is at 346 nm for the native protein with a broad band width and
for fully unfolded protein(thermal) at 350 nm. Is it possible that most
of the protein molecles are in an unfolded state? How do I check this?
(The protein is in 10mM Tris-Cl, pH 7.5).  From other structures ~25-30%
of trp is exposed.  Also KI would bind to exposed Trp in folded and in
unfolded proteins.
2)      How is the correction for decrease in fluorescence due to increasing
temperature is done in thermal unfolding?
                Thanks for all suggestions.
                                        Bhupesh. 17-3-99.
                                bhupesh at lion.imtech.ernet.in
                                bhupesh at bragg.imtech.ernet.in