ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The secondary structure transformation of β-lactoglobulin from a predominantly β-structure into a predominantly α-helical one, under the influence of solvent polarity changes is reversible. Independent of the alcohol used - methanol, ethanol, or 2-propanol - the midpoints of the observed structural transformation occur around dielectric constant ε ≈ 60. The structural change destroying the hydrophobic core formed by the β-barrel structure leads, at room temperature, to the dissociation of the retinol/β-lactoglobulin complex in the neighborhood of dielectric constant ε ≈ 50. However, when the dielectric constant of the medium is raised back to ε ≈ 70 by the decrease of the temperature, both the refolding of BLG into a β-structure and the reassociation of the retinol/β-lactoglobulin complex are observed. The esterification of β-lactoglobulin carboxyl groups has two effects: on the one hand it accelerates the β-strand → α-helix transition induced by alcohols. On the other hand, the esterification of β-lactoglobulin strengthens its interaction with retinol as it may be deduced from the smaller apparent dissociation constant of retinol/methylated β-lactoglobulin complex. The binding of retinol to modified or unmodified β-lactoglobulin has no influence (stabilizing or destabilizing) on the folding changes induced by alcohol. © 1993 John Wiley & Sons, Inc.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360330408
