SPECTRAL ANALYSIS OF THE EFFECTS OF CALCIUM ION ON ALPHA CRYSTALLIN CONFORMATION

Norfolk State University, Norfolk VA

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Linked publications & trials

Abstract

The long-term objective of this project is to determine the effects of the presence of calcium ion on the[unreadable] configuration of the ocular lens protein alpha-crystallin. Ocular lens transparency depends on the specific[unreadable] packing of proteins that are synthesized. It has been shown that a-crystallin, a major protein component of[unreadable] the ocular lens, plays an important role in maintaining the transparency of the lens. It prevents heat-induced[unreadable] and photo-aggregation of other crystallins and enzymes by acting like a molecular chaperone. The[unreadable] chaperone-like activity of a-crystallin is believed due to the protein providing properly placed hydrophobic[unreadable] surfaces upon which the damaged protein interacts. It is thought that this chaperone-like behavior may be[unreadable] important in preventing cataract formation. Since it has been discovered that a-crystallin acts as a[unreadable] molecular chaperone under various denaturing conditions, research has focused on determining this[unreadable] mechanism of action that is thought to be protein conformation dependent. It is of interest to determine[unreadable] conditions which bring about this reduction in the chaperone ability of a-crystallin. It is hypothesized that acrystallin's[unreadable] configuration, and thus its chaperone-like behavior, is affected when its configuration is altered[unreadable] under stress conditions such as exposure to near-UV radiation. This proposal (prepared in collaboration[unreadable] with Dr. Lisa Hibbard (Spelman College) sets forth studies to investigate the effects of solvent ionic strength[unreadable] on the configuration and chaperone-like activity of a-crystallin and the lens structural protein, b-crystallin.[unreadable] Since it has been recently proposed that calcium binding may have either a deleterious or pivotal role in the[unreadable] chaperone-like behavior of a-crystallin depending on the concentration of ion present, ionic strength studies[unreadable] are relevant as it is known that the concentration of certain ions, in particular Na+ and Ca2+, can vary under[unreadable] given conditions in the ocular lens, particularly those in which cataracts are present. The combination of[unreadable] increased solvent ionic strength and exposure of aqueous solutions of a-crystallin to UV-A radiation will also[unreadable] be studied. It is of interest to determine whether the varying solvent conditions and exposure to UV radiation[unreadable] affects the ability of a-crystallin to protect b-crystallin upon heating. The project will study the effects of[unreadable] calcium ion on native and damaged protein conformation using both FTIR (and deconvoluted peak data) and[unreadable] far-UV CD spectra (done at Spelman College).