Physicochemical binding properties of the proteoglycan receptor for serum lipoproteins.
Proteoheparan sulfate can be adsorbed to a methylated silica surface in a monomolecular layer via its transmembrane hydrophobic protein core domain. Due to electrostatic repulsion, its anionic polysugar side chains are stretched out into the blood substitute solution representing a co-receptor for specific lipoprotein binding through basic amino acid-rich residues within their apolipoproteins. The binding process was studied by ellipsometric techniques showing that oxLDL had a deleterious effect on heparan sulfate proteoglycan binding and conformation. Ca2+ binding to and storage on the proteoheparan sulfate/LDL compound formed a 'heterotrimeric' HS-PG/LDL/Ca2+ complex of high stability, aggregability and deposit coating. On the other hand, HDL bound to heparan sulfate proteoglycan protected against LDL docking and completely suppressed calcification of the proteoglycan/lipoprotein complex.
Siegel
G
G
Institute of Physiology, Biophysical Research Group, The Free University of Berlin, Germany.
Malmsten
M
M
Klüssendorf
D
D
Leonhardt
W
W
D000327:Adsorption; D001665:Binding Sites; D015374:Biosensing Techniques; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood*; D011485:Protein Binding / Q000502:physiology; D012680:Sensitivity and Specificity; D012825:Silicon; D013499:Surface Properties
D019812:Heparan Sulfate Proteoglycans; D008077:Lipoproteins, LDL; D002118:Calcium; D012825:Silicon