7p53 | pdb_00007p53
Crystal Structure of Human gamma-D-crystallin mutant C110M at 1.57 Angstroms resolution
Structural highlights
DiseaseCRGD_HUMAN Defects in CRYGD are a cause of cataract autosomal dominant (ADC) [MIM:604219. Cataract is an opacification of the crystalline lens of the eye that frequently results in visual impairment or blindness. Opacities vary in morphology, are often confined to a portion of the lens, and may be static or progressive. In general, the more posteriorly located and dense an opacity, the greater the impact on visual function. Cataract is the most common treatable cause of visual disability in childhood.[1] [2] [3] Defects in CRYGD are the cause of cataract congenital non-nuclear polymorphic autosomal dominant (CCP) [MIM:601286; also known as polymorphic congenital cataract. A congenital cataract characterized by a non-progressive phenotype and partial opacity that has a variable location between the fetal nucleus of the lens and the equator. The fetal nucleus is normal. The opacities are irregular and look similar to a bunch of grapes and may be present simultaneously in different lens layers.[4] [5] Defects in CRYGD are the cause of cataract congenital cerulean type 3 (CCA3) [MIM:608983; also known as congenital cataract blue dot type 3. A cerulean form of autosomal dominant congenital cataract. Cerulean cataract is characterized by peripheral bluish and white opacifications organized in concentric layers with occasional central lesions arranged radially. The opacities are observed in the superficial layers of the fetal nucleus as well as the adult nucleus of the lens. Involvement is usually bilateral. Visual acuity is only mildly reduced in childhood. In adulthood, the opacifications may progress, making lens extraction necessary. Histologically the lesions are described as fusiform cavities between lens fibers which contain a deeply staining granular material. Although the lesions may take on various colors, a dull blue is the most common appearance and is responsible for the designation cerulean cataract. Defects in CRYGD are the cause of cataract crystalline aculeiform (CACA) [MIM:115700. A congenital crystalline cataract characterized by fiberglass-like or needle-like crystals projecting in different directions, through or close to the axial region of the lens. The opacity causes a variable degree of vision loss.[6] FunctionCRGD_HUMAN Crystallins are the dominant structural components of the vertebrate eye lens. Publication Abstract from PubMedHuman gammaD-crystallin (HGD) has remarkable stability against condensation in the human lens, sometimes over a whole lifetime. The native protein has a surface exposed free cysteine that forms dimers (Benedek, 1997; Ramkumar et al., 1864)(1,2) without specific biological function and leads to further protein association and/or aggregation, which creates a paradox for understanding its stability. Previous work has demonstrated that chemical modification of the protein at the free cysteine (C110), increases the temperature at which liquid-liquid phase separation occurs (LLPS), lowers protein solubility and suggests an important role for this amino acid in maintaining its long-term resistance to condensation. Here we demonstrate that mutation of the cysteine does not alter the structure or solubility (liquidus) line for the protein, but dramatically increases the protein crystal nucleation rate following LLPS, suggesting that the free cysteine has a vital role in suppressing crystallization in the human lens. Surface Exposed Free Cysteine Suppresses Crystallization of Human gammaD-Crystallin.,Strofaldi A, Khan AR, McManus JJ J Mol Biol. 2021 Sep 16;433(22):167252. doi: 10.1016/j.jmb.2021.167252. PMID:34537240[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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