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From Proteopedia
Crystal structure of truncated human beta-B1-crystallin
Structural highlights
DiseaseCRBB1_HUMAN Defects in CRYBB1 are the cause of cataract congenital nuclear autosomal recessive type 3 (CATCN3) [MIM:611544. A congenital cataract affecting the central nucleus of the eye. Nuclear cataracts are often not highly visually significant. The density of the opacities varies greatly from fine dots to a dense, white and chalk-like, central cataract. The condition is usually bilateral. Nuclear cataracts are often combined with opacified cortical fibers encircling the nuclear opacity, which are referred to as cortical riders.[1] Defects in CRYBB1 are a cause of cataract-microcornea syndrome (CAMIS) [MIM:116150. An ocular disorder characterized by the association of congenital cataract and microcornea without any other systemic anomaly or dysmorphism. Clinical findings include a corneal diameter inferior to 10 mm in both meridians in an otherwise normal eye, and an inherited cataract, which is most often bilateral posterior polar with opacification in the lens periphery. The cataract progresses to form a total cataract after visual maturity has been achieved, requiring cataract extraction in the first to third decade of life. Microcornea-cataract syndrome can be associated with other rare ocular manifestations, including myopia, iris coloboma, sclerocornea and Peters anomaly. Transmission is in most cases autosomal dominant, but cases of autosomal recessive transmission have recently been described.[2] [:] FunctionCRBB1_HUMAN Crystallins are the dominant structural components of the vertebrate eye lens. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCrystallins are long-lived proteins packed inside eye lens fiber cells that are essential in maintaining the transparency and refractive power of the eye lens. Members of the two-domain betagamma-crystallin family assemble into an array of oligomer sizes, forming intricate higher-order networks in the lens cell. Here we describe the 1.4 angstroms resolution crystal structure of a truncated version of human betaB1 that resembles an in vivo age-related truncation. The structure shows that unlike its close homolog, betaB2-crystallin, the homodimer is not domain swapped, but its domains are paired intramolecularly, as in more distantly related monomeric gamma-crystallins. However, the four-domain dimer resembles one half of the crystallographic bovine betaB2 tetramer and is similar to the engineered circular permuted rat betaB2. The crystal structure shows that the truncated betaB1 dimer is extremely well suited to form higher-order lattice interactions using its hydrophobic surface patches, linker regions, and sequence extensions. Crystal structure of truncated human betaB1-crystallin.,Van Montfort RL, Bateman OA, Lubsen NH, Slingsby C Protein Sci. 2003 Nov;12(11):2606-12. PMID:14573871[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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