Conformation of mucous glycoproteins in aqueous solvents

✍ Scribed by R. L. Shogren; A. M. Jamieson; J. Blackwell; N. Jentoft

• Publisher: Wiley (John Wiley & Sons)
• Year: 1986
• Tongue: English
• Weight: 752 KB
• Volume: 25
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360250809

✦ Synopsis

Synopsis

Light-scattering techniques have been used to measure the z-average radius of gyration R, z-average translational diffusion coefficient Dt and weight-average molecular weight M , of porcine submaxillary much (PSM) in solution. PSM isolated at low shear in the presence of protease inhibitors has a M , about twice as large as a sample prepared without these precautions. The former sample has a M, of 17 X lo6 in 0.1M NaCI, which decreases to 8 X lo6 in 6M guanidine hydrochloride (GdnHC1) and then to 2 X lo6 on addition of 0.1M mercaptoethanol to the 6M GdnHCl solution. The R , or 0 ; ' values obtained for PSM in this work superimpose with those of other authors for different mucin glycoproteins, leading to linear log-log relationships to the molecular weight of the protein core. Comparison of these results with those in the literature for denatured proteins suggest that mucins are linear random coils in which the protein core is stiffened by the presence of the oligosaccharide side chains. The length of the oligasaccharides and the nature of the solvent have little effect on the extension of the protein core. This suggests that the stiffness of the protein core is maintained by steric repulsion of the residues at the beginning of the oligosaccharide chains.