Enthalpy and Entropy of Hydration of Bovine Crystallins (*)
- ↵¶ To whom correspondence should be addressed: Chemistry Dept., Adelphi University, Garden City, NY 11530. Tel.: 516-877-4135; Fax: 516-877-4191.
Abstract
Transparency of the lens of the eye is the result of a short range order in the packing of crystallin molecules within the
fiber cells. Short range order depends on crystallin-crystallin as well as water-crystallin interactions. Light scattering
measurements can provide information on the hydration of crystallins. Light scattering intensities were obtained as a function
of scattering angle, concentration, and temperature on dilute solutions of β
, β
, and 
fractions of bovine lens crystallins. The temperature dependence of the second virial coefficient was negative for the β
crystallin fractions and positive for the 
fraction as well as that for α crystallin (Wang, X., and Bettelheim, F. A.(1989) Proteins Struct. Funct. Genet. 5, 166-169). The partial molar enthalpy values of the solutions were negative for the β crystallin fractions, indicating
a tendency for homo- and heterodimer and -oligomer association. The enthalpy values were positive for the α and 
fractions. The negative values of the enthalpy of solutions differentiate the β crystallins from the other crystallins. The
partial molar entropy values of solutions of β
and 
fractions were identical, those of the oligomeric β
fraction were higher, whereas those of α crystallin were a magnitude larger than those of the the smaller crystallin molecules.
Footnotes
-
↵* This work was supported in part by National Institutes of Health Grant EY-02571 (to F. A. B.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
- Received April 27, 1995.
- Revision received August 22, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
