title: Molecular structure and rheological properties of short-side-chain heavily glycosylated porcine stomach mucin.
abstract: The current accepted model for high-molecular-weight gastric mucins of the MUC family is that they adopt a polydisperse coil conformation in bulk solutions. We develop this model using well-characterized highly purified porcine gastric mucin Orthana that is genetically close to the human MUC6 type. It has short side chains and low levels of sialic acid residues and includes minute amounts of cysteine residues that, if abundant, can be responsible for the self-polymerization of mucin. We have established that the mucin structure in bulk solutions corresponds to a daisy-chain random coil. Dynamic light scattering experiments probe the internal dynamics of globular subunits (individual daisies) at the approximately 9 nm length scale, whereas viscosity and light scattering measurements indicate that the size of the whole mucin chains is much larger, approximately 50 nm. The bulk viscosity (eta) scales with mucin concentration (c) in a manner similar to that found for short-side-chain synthetic comb polyelectrolytes and is characterized by a transition between semidilute (eta approximately c1/2) and entangled (eta approximately c3/2) regimes.
authors.affiliation: Unilever Corporate Research, Colworth Park, Sharnbrook, Bedfordshire, United Kingdom. gleb.yakubov@unilever.com
authors.forename: Gleb E
authors.initials: GE
authors.lastname: Yakubov
authors.forename: Aristeidis
authors.initials: A
authors.lastname: Papagiannopoulos
authors.forename: Elodie
authors.initials: E
authors.lastname: Rat
authors.forename: Richard L
authors.initials: RL
authors.lastname: Easton
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Waigh
mesh_terms: D000818:Animals; D002118:Calcium / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D005752:Gastric Mucins / Q000737:chemistry*; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009005:Monosaccharides / Q000737:chemistry; D012212:Rheology; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D013552:Swine; D014783:Viscosity
chemical_list: D005752:Gastric Mucins; D009005:Monosaccharides; D012996:Solutions; D002118:Calcium