These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Zn2+ enhances the molecular chaperone function and stability of alpha-crystallin.
    Author: Biswas A, Das KP.
    Journal: Biochemistry; 2008 Jan 15; 47(2):804-16. PubMed ID: 18095658.
    Abstract:
    Alpha-crystallin, the major eye lens protein, is a molecular chaperone that plays a crucial role in the suppression of protein aggregation and thus in the long-term maintenance of lens transparency. Zinc is a micronutrient of the eye, but its molecular interaction with alpha-crystallin has not been studied in detail. In this paper, we present results of in vitro experiments that show bivalent zinc specifically interacts with alpha-crystallin with a dissociation constant in the submillimolar range (Kd approximately 0.2-0.4 mM). We compared the effect of Zn2+ with those of Ca2+, Cu2+, Mg2+, Cd2+, Pb2+, Ni2+, Fe2+, and Co2+ at 1 mM on the structure and chaperoning ability of alpha-crystallin. An insulin aggregation assay showed that among the bivalent metal ions, only 1 mM Zn2+ improved the chaperone function of alpha-crystallin by 30% compared to that in the absence of bivalent metal ions. Addition of 1 mM Zn2+ increased the yield of alpha-crystallin-assisted refolding of urea-treated LDH to its native state from 33 to 38%, but other bivalent ions had little effect. The surface hydrophobicity of alpha-crystallin was increased by 50% due to the binding of Zn2+. In the presence of 1 mM Zn2+, the stability of alpha-crystallin was enhanced by 36 kJ/mol, and it became more resistant to tryptic cleavage. The implications of enhanced stability and molecular chaperone activity of alpha-crystallin in the presence of Zn2+ are discussed in terms of its role in the long-term maintenance of lens transparency and cataract formation.
    [Abstract] [Full Text] [Related] [New Search]