Biglycan and decorin bind close to the n-terminal region of the collagen VI triple helix.
The binding of native biglycan and decorin to pepsin-extracted collagen VI from human placenta was examined by solid phase assay and by measurement of surface plasmon resonance in the BIAcore(TM)2000 system. Both proteoglycans exhibited a strong affinity for collagen VI with dissociation constants (K(D)) of approximately 30 nm. Removal of the glycosaminoglycan chains by chondroitinase ABC digestion did not significantly affect binding. In coprecipitation experiments, biglycan and decorin bound to collagen VI and equally competed with the other, suggesting that biglycan and decorin bind to the same binding site on collagen VI. This was confirmed by electron microscopy after negative staining of complexes between gold-labeled proteoglycans and collagen VI, demonstrating that both biglycan and decorin bound exclusively to a domain close to the interface between the N terminus of the triple helical region and the following globular domain. In solid phase assay using recombinant collagen VI fragments, it was shown that the alpha2(VI) chain probably plays a role in the interaction.
Wiberg
C
C
Department of Cell and Molecular Biology, University of Lund, BMC Plan C12, Lund S-221 84, Sweden.
Hedbom
E
E
Khairullina
A
A
Lamandé
S R
SR
Oldberg
A
A
Timpl
R
R
Mörgelin
M
M
Heinegård
D
D
D000818:Animals; D058578:Biglycan; D001667:Binding, Competitive; D016466:CHO Cells; D002417:Cattle; D019765:Chondroitin ABC Lyase / Q000494:pharmacology; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism*; D006224:Cricetinae; D058575:Decorin; D004305:Dose-Response Relationship, Drug; D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D008854:Microscopy, Electron; D010920:Placenta / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020349:Surface Plasmon Resonance
C546884:BGN protein, human; D058578:Biglycan; C546878:DCN protein, human; D058575:Decorin; D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D011509:Proteoglycans; D011994:Recombinant Proteins; D003094:Collagen; D019765:Chondroitin ABC Lyase