Description
Product Characteristics:
Crystallins are the major proteins of the vertebrate eye lens, where they maintain the transparency and refractive index of the lens. Crystallins are divided into Alpha, Beta, and Gamma families, and the Beta- and Gamma-crystallins also comprise a superfamily. Crystallins usually contain seven distinctive protein regions, including four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins constitute the major lens structural proteins, and they associate into dimers, tetramers, and higher order aggregates. The Beta-crystallin subfamily is composed of several gene products, including Beta A1-, Beta A2-, Beta A3-, Beta A4-, Beta B1-, Beta B2- and Beta B3-crystallin. The Beta A1- and Beta A3-crystallin proteins are encoded by a single mRNA. They differ by only 17 amino acids, and Beta A1-crystallin is generated by use of an alternate translation initiation site.
Subcellular location: Cytoplasm, Nucleus
Synonyms: Beta crystallin B1, Beta-B1 crystallin, Beta-crystallin B1, CRBB1_HUMAN, CRYBB 1, Crybb1, Crystallin beta B1, Eye lens structural protein, OTTHUMP00000028719.
Target Information: Crystallins are separated into two classes taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families\, beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups. Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, undergoes extensive cleavage at its N-terminal extension during lens maturation. It is also a member of a gene cluster with beta-A4, beta-B2, and beta-B3. [provided by RefSeq, Jul 2008]