Temperature-dependent shift of fluorescence spectra without conformational changes in protein; studies of dipole relaxation in the melittin molecule.
When studying bee venom melittin in an ordered tetrameric form we found a shift of the fluorescence spectrum to a longer wavelength with a rise in temperature above 25 degrees C. The application of the methods of circular dichroism, temperature-perturbation difference spectrophotometry, gel filtration, ionic quenching and polarization of Trp-19 fluorescence argues against the possibility of dissociation and change in conformation with the rise in temperature. The spectral shifts are, probably, caused by dipole-orientational structural relaxation of the tryptophanyl environment in the excited state at nanosecond times. The dependence of the fluorescence spectrum on the excitation wavelength was found to be a function of temperature. This function was applied to determine the dipole-orientational relaxation times.
Demchenko
A P
AP
A.V. Palladin Institute of Biochemistry, Academy of Sciences of the Ukrainian SSR, Kiev.
Ladokhin
A S
AS
D000465:Algorithms; D000818:Animals; D001514:Bee Venoms / Q000032:analysis; D002942:Circular Dichroism; D005454:Fluorescence Polarization; D008555:Melitten; D009994:Osmolar Concentration; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013696:Temperature
D001514:Bee Venoms; D008555:Melitten