Conformational changes in human serum albumin studied by fluorescence and absorption spectroscopy. Distance measurements as a function of pH and fatty acids.
pH- and fatty acid-induced conformational changes in human serum albumin were investigated by fluorescence-energy transfer, determining the distance between Trp-214 and bound bilirubin at 25 degrees C. This distance changes significantly with the pH, being 2.52 +/- 0.01 nm at pH 6, 2.31 +/- 0.04 nm at pH 9, 2.13 +/- 0.07 nm at pH 11.0 and 2.77 nm at pH 11.9. The influence of different fatty acids on the distance was also determined. At pH 7.4 medium-chain fatty acids seem to increase this distance, whereas long-chain fatty acids, at low concentrations, decrease the distance between the two chromophores. The contraction of the protein carrying long-chain saturated fatty acids is even more pronounced at pH 9.
Honoré
B
B
Institute of Medical Biochemistry, University of Aarhus, Denmark.
Pedersen
A O
AO
D001663:Bilirubin; D005227:Fatty Acids; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D012709:Serum Albumin; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic; D014364:Tryptophan
D005227:Fatty Acids; D012709:Serum Albumin; D014364:Tryptophan; D001663:Bilirubin