Disulfide crosslinks in lens crystallin proteins

Lens crystallin proteins, including the alpha, beta, and gamma families, are among the longest-lived proteins in the human body and do not undergo turnover throughout an individual's life. Over time, these proteins are subject to cumulative oxidative stress, which leads to the formation of covalent disulfide crosslinks between cysteine residues. This process results in the formation of high-molecular-weight protein aggregates that scatter light and increase the mechanical stiffness of the lens. These molecular changes are the primary drivers of age-related vision conditions such as cataracts (opacification) and presbyopia (loss of accommodative flexibility). Therapeutic strategies, such as the use of lipoic acid choline ester (UNR844), target these crosslinks by acting as reducing agents that break the disulfide bonds. By restoring the proteins to their native, soluble state, these treatments aim to improve lens clarity and restore the eye's ability to focus on near objects. (Sources: Truscott, R. J., 2005, Experimental Eye Research; Garner, W. H., & Garner, M. H., 2016, Investigative Ophthalmology & Visual Science; Novartis, 2020).

Other names

Crystallin disulfide bondsLens protein aggregatesOxidized crystallinsIntermolecular disulfide crosslinksCrystallin-thiol mixed disulfides

Reduction of intermolecular disulfide bonds back to sulfhydryl groups to restore protein solubility and lens flexibility.