ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The conformation of β-casein A in the monomeric and thermally aggregated states has been investigated by a range of techniques. β-Casein exists as a monomer in solution at 4°C and at concentrations up to at least 3 g/dl. The molecule is flexible and exhibits a lot of segmental motion, but its secondary structure is not wholly random coil; about one-third of the polypeptide chain is ordered and the likely locations of these regions are discussed. The radius of gyration, representing the time-average distribution of the flexible chain, is 46 Å. Increasing temperature leads to aggregation of the β-casein molecules. The degree of association is very sensitive to experimental conditions, and under our conditions a 14-mer exists at 20°C. The aggregate is spherical with a radius of about 100 Å. The interior of the aggregate is relatively disordered, and the β-casein molecules remain in a largely flexible, hydrated conformation. The volume restriction of the protein molecules which occurs on association leads to some immobilization of the hydrophobic C-terminal region, which is packed toward the center of the aggregate.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1979.360180507
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