beta sheet

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beta sheet

n.
A secondary structure that occurs in many proteins and consists of two or more parallel adjacent polypeptide chains arranged in such a way that hydrogen bonds can form between the chains. Also called beta pleated sheet, pleated sheet.

beta sheet

A protein configuration resulting from the alignment of multiple adjacent beta strands and formation of hydrogen bonds between them. The beta sheet is a major secondary protein structure motif elucidated by Pauling and Corey, which consists of polypeptide chains in sheets laid side-by-side and are almost completely extended, with an axial distance of 35 nm vs an axial distance of 15 nm in the helix. The PS is stabilised by hydrogen bonds between NH and CO groups of different polypeptide strands; adjacent molecules may run in the same direction (parallel) or in the opposite (antiparallel) direction—e.g., silk fibroin. The PS is a tertiary structure elucidated by X-ray crystallography and seen by EM; it can be produced experimentally by treating Bence-Jones proteins with enzymes, and is a structure typical of amyloidosis. The PS may be seen by the Congo red stain with polarising light to reveal the characteristic apple-green birefringence.
 
EM
Extracellular 700–1000 nm in diameter, fine complex non-branching fibrils.

beta sheet

A protein structure in which parallel layers of linked peptides are folded across each other. This structure is characteristic of amyloid proteins.
See also: sheet
References in periodicals archive ?
This is Pten tumor suppressor protein, chosen because it contains alpha-helices, beta-pleated sheets, and coils.
Beta-pleated sheets (strands) are orange arrows pointing from the free amino end to the free carboxyl end.
The three common features of all types of amyloid are the typical ultrastructure of amyloid fibrils as seen on electron microscopy, (20) confirmation of the characteristic cross beta-pleated sheet on x-ray crystallography and infrared spectroscopy, (21) and the presence of an amyloid serum precursor that already has a high degree of cross beta-pleated sheet structure.
Biopsy the affected organ * Congo red binding and green birefringence under polarized light * Fibril structure on electron microscopy * X-ray crystallography and infrared spectroscopy to confirm the characteristic cross beta-pleated sheet * Biochemical and/or immunohistochemical identification of the major amyloid protein * For patients with the AL type of amyloid: Immunohistochemical staining: demonstration of kappa and lambda chains in plasma cells Molecular genetic methods: differentiation between poly- and monoclonal B cells Step 2.
Beta-pleated sheets were correctly predicted approximately half the time, and beta bends were predicted with even slightly better accuracy.
Photo: Part of the tertiary structure of the enzyme lactate dehydrogenase, showing the spatial arrangement of its alpha helices and beta-pleated sheets.
But all of them go bad in a similar way, twisting from loose, flexible molecules into rigid, sticky formations known as beta-pleated sheets.
Every protein in the body probably has the ability to form beta-pleated sheets given the right (or wrong) circumstances, says Erich Wanker, a molecular biologist and biochemist at the Max Delbruck Center for Molecular Medicine in Berlin.