Light and X-ray scattering show decorin to be a dimer in solution.
Decorin is a widely distributed member of the extracellular matrix small leucine-rich repeat glycoprotein/proteoglycan family. For investigation of its physical properties, decorin from two sources (young steer skin and a recombinant adenovirus) was used. The first sample was extracted into 7 m urea and purified, while the second was isolated from medium conditioned by 293A cells infected with adenovirus and purified without chaotropes. The only chemical differences detected between these materials were a slightly shorter glycosaminoglycan chain and the retention of the propeptide on the latter. Circular dichroism spectra of the two samples were virtually identical, showing a high proportion of beta-sheet and beta-turn and little alpha-helix. The protein cores were completely denatured in 2.25 m guanidine HCl (GdnHCl) but recovered their secondary structure on removal of chaotrope. Light scattering of material eluted from gel-filtration columns in Tris-buffered saline, pH 7.0, gave molecular mass values of 165 +/- 1 kDa and 84.6 +/- 4 kDa for intact decorin and the glycoprotein core produced by digestion with chondroitin ABC lyase, respectively. Intact recombinant prodecorin had a mass of 148 +/- 18 kDa. These values, which are double those estimated from SDS gel electrophoresis or from the known sequences and compositions, were halved in 2.5 m GdnHCl. Data from solution x-ray scattering of intact decorin and its core in Tris-buffered saline are consistent with a dimeric particle whose protein component has a radius of gyration of 31.6 +/- 0.4 A, a maximum diameter of 98 +/- 5 A, and approximates two intertwined C shapes.
Scott
Paul G
PG
Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada. Paul.Scott@ualberta.ca
Grossmann
J Gunter
JG
Dodd
Carole M
CM
Sheehan
John K
JK
Bishop
Paul N
PN
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002417:Cattle; D002460:Cell Line; D019765:Chondroitin ABC Lyase / Q000494:pharmacology; D002942:Circular Dichroism; D017077:Culture Media, Conditioned / Q000494:pharmacology; D058575:Decorin; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D016326:Extracellular Matrix Proteins; D019791:Guanidine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D017433:Protein Structure, Secondary; D011509:Proteoglycans / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012542:Scattering, Radiation; D014965:X-Rays
D017077:Culture Media, Conditioned; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D011994:Recombinant Proteins; D019765:Chondroitin ABC Lyase; D019791:Guanidine