The Gross Conformation of Mucus Glycoproteins in Solution

What domains do these mucin assemblies described herein occupy in solution How do they interact with each other and with other molecules to form the mucosal ba er In answer to the first question, there is growing evidence to suggest that they occupy enormously expanded, and thus, at low concentration ( 1%), readily overlapping, spheroidal domains in solution. 

Besides being enormously expanded and spheroidal, the mucins also appear very flexible evidence for this derives from the ease with which these molecules are deformed with shear, as shown in streaming-birefringence experiments, from the concentration dependence of viscosity, and the temperature-dependence of sedimentation coeflScients. Mikkelsen and co-workers confirmed these observations by using the dependence on field strength of electric birefringence relaxation-phenomena. Evidence for local flexibility in the carbohydrate side-chains has come from, for example, n.m.r.-spectral studies.  

Finally, the existence of mucins in solution as highly expanded, spheroidal domains is also consistent with their biological function as space-filling 

One important feature of mucins is their behavior as polyelectrolytes for example, this has been postulated as a possible control-mechanism in the periodic changes in cervical mucus. This behavior is a result of the relatively large proportion of acidic sugar residues (NeuAc) normally present. 

Tam and Verdugo observed that changes in pH over the range of 6.5 - 

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