The macromolecular structure of human cervical-mucus glycoproteins. Studies on fragments obtained after reduction of disulphide bridges and after subsequent trypsin digestion.
Human cervical-mucus glycoproteins (mucins) were extracted with 6 M-guanidinium chloride in the presence of proteinase inhibitors and purified by isopycnic density-gradient centrifugation. The whole mucins (Mr approx. 10 X 10(6] were degraded into 'subunits' (Mr approx. 2 X 10(6] by reduction of disulphide bonds. Trypsin digestion of the 'subunits' produced glycopeptides with Mr approx. 380000, which appear to be rod-like with a length of approx. 105 nm. The relationship between the radius of gyration and the Mr value obtained by light-scattering for whole mucins, 'subunits' and 'domains' suggest that cervical-mucus glycoproteins are linear flexible macromolecules composed of, on the average, four or five 'domains'/subunit and four subunits/whole mucin macromolecule. The shape-dependent particle scattering function for the whole mucins and the 'subunits' are in accordance with that of a linear flexible chain. No evidence for a branched or a star-like structure was found. A tentative model for cervical mucins is proposed.
D000596:Amino Acids / Q000032:analysis; D002500:Centrifugation, Isopycnic; D002582:Cervix Mucus / Q000032:analysis*; D002850:Chromatography, Gel; D004229:Dithiothreitol; D005260:Female; D006801:Humans; D008027:Light; D046911:Macromolecular Substances; D008956:Models, Chemical; D009077:Mucins / Q000302:isolation & purification; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000302:isolation & purification; D012542:Scattering, Radiation; D014357:Trypsin
D000596:Amino Acids; D046911:Macromolecular Substances; D009077:Mucins; D010446:Peptide Fragments; D014357:Trypsin; D004229:Dithiothreitol