Synthetic collagen-like domain derived from the macrophage scavenger receptor binds acetylated low-density lipoprotein in vitro.
The bovine macrophage scavenger receptor is a 70 kDa membrane protein that is trimerized on the macrophage cell surface. The receptor binds modified low-density lipoproteins (LDL). The core binding site is located within 22 residues at the C-terminus of the collagen-like domain of the receptor. The Lys residue at position 337 plays an important role in ligand binding. Here, the collagen-like domain was constructed using a peptide architecture technique, in which three collagenous peptide chains were crosslinked at their N-termini. The crosslinked peptide showed a collagen-like structure by circular dichroism and existed mainly in a monomeric triple helical form as shown by gel exclusion chromatography. The triple-stranded peptide was demonstrated to bind acetylated LDL (Ac-LDL) using regions derived from Gly323 to Lys340 of the natural bovine scavenger receptor. However, a single-stranded peptide with the same amino acid sequence did not bind Ac-LDL. Furthermore, a triple-stranded mutated peptide in which Lys corresponding to Lys337 in the mother protein was substituted with Ala showed no binding activity to Ac-LDL. These results, taken together, indicate that the synthetic collagen-like peptide has a similar structure to the binding site in the scavenger receptor, and support the view that the collagen-like domain of the natural scavenger receptor recognizes Ac-LDL.
Tanaka
T
T
Protein Engineering Research Institute, Osaka, Japan.
Nishikawa
A
A
Tanaka
Y
Y
Nakamura
H
H
Kodama
T
T
Imanishi
T
T
Doi
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003094:Collagen / Q000737:chemistry*; D015195:Drug Design; D007202:Indicators and Reagents; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000378:metabolism*; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D013816:Thermodynamics
D007202:Indicators and Reagents; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D010446:Peptide Fragments; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; C032629:acetyl-LDL; D003094:Collagen