Rotational mobility associated with the protein moiety of human serum lipoproteins from tryptophan phosphorescence anisotropy measurements.
The steady-state phosphorescence anisotropy of human low density (LDL) and very low density (VLDL) serum lipoproteins in a glycerol--buffer solvent has been investigated. By virtue of the long lifetime of the triplet state, depolarization of the emission resulting from slow rotational motions is observed between -90 and -50 degrees C. Despite the number of emitting residues within these complexes, the rotational behavior can be represented within experimental error by a single correlation time. The magnitude and temperature dependence of the rotational correlation times observed for LDL are consistent with overall rotation of essentially spherical rigid particles as the source of the phosphorescence depolarization. Preliminary data for VLDL indicate the presence of internal peptide motions which are more rapid than those of the overall complex.
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006801:Humans; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D008163:Luminescent Measurements; D013696:Temperature; D014364:Tryptophan
D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014364:Tryptophan