Fluorescence studies of a high density serum lipoprotein

✍ Scribed by C.J. Hart; R.B. Leslie; A.M. Scanu

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 322 KB
• Volume: 4
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(70)90036-8

✦ Synopsis

The naturally occurring, water-soluble serum lipoprotein, HDL2, has been studied by fluorescence techniques. 2. HDL2 has fluorescence characteristics similar to those of the lipid-free protein (ctP2).

This suggests that the binding of lipid to the protein has not markedly affected the protein conformation. Intensity and wavelength studies indicate that the lipid in HDL2 affords the protein some protection from thermal and urea denaturation. 3. The binding of a fluorescent probe, ANS, to the apoprotein (ctP~) reveals the presence of three hydrophobic sites on each protein molecule. 4. HDL2 binds approximately 300 molecules of ANS with a concomitant 200-fold increase in fluorescence intensity. A comparison with an egg yolk lecithin dispersion in water suggests that all the lipid is accessible to ANS. 5. The results are consistent with previous NMR studies, suggesting that the organization of the lipids and proteins is much looser than occurs in erythrocyte membranes. Protein:protein, as well as lipid:protein interactions may be involved in maintaining the structural integrity of HDL2.