Conformational changes of human serum albumin in vivo induced by free fatty acids as studied by Fourier transform infrared spectroscopy.
Binding of free fatty acids (FFA) to human serum albumin (HSA) was studied by Fourier transform infrared (FT-IR) spectroscopy. Six volunteers ran a marathon race in order to induce changes in their basal plasma FFA levels. Three volunteers were well-trained and three untrained. The non-deconvolved HSA spectra show two types of spectra: the first one includes the untrained runners, who, after the run, display noticeable changes in the absorbance intensity of the amide I band, which also shifts to higher frequencies. The second one includes the well-trained subjects who exhibit few changes after the race. Examination of the deconvolved spectra of HSA shows two types of spectra, as well: the first class displays important decreases in the absorbance of the component assigned to alpha-helix after the race, together with a gradual growth of the two components that can be assigned to turns. The second class, which includes the well-trained subjects, exhibits few changes after the run. These data are interpreted in terms of conformational changes due to a less ordered alpha-helix state of HSA after FFA binding, while the emergence of components assigned to turns may reflect the exposure of several histidine residues to the solvent (which are buried in HSA when FFA/HSA less than 4). Our data are consistent with the Karush model of FFA to HSA binding.
Le Gal
J M
JM
Laboratoire de Spectroscopie Biomoléculaire, Faculté de Pharmacie, Reims, France.
Manfait
M
M
D000328:Adult; D005230:Fatty Acids, Nonesterified / Q000737:chemistry* / Q000378:metabolism; D005583:Fourier Analysis; D006801:Humans; D005082:Physical Exertion; D010809:Physical Fitness; D011485:Protein Binding; D011487:Protein Conformation; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared
D005230:Fatty Acids, Nonesterified; D012709:Serum Albumin