The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet. A β-strand is a stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation. The supramolecular association of β-sheets has been implicated in the formation of the fibrils and protein aggregates observed in amyloidosis, notably Alzheimer's disease. The first β-sheet structure was proposed by William Astbury in the 1930s. He proposed the idea of hydrogen bonding between the peptide bonds of parallel or antiparallel extended β-strands. However, Astbury did not have the necessary data on the bond geometry of the amino acids in order to build accurate models, especially since he did not then know that the peptide bond was planar. The majority of β-strands are arranged adjacent to other strands and form an extensive hydrogen bond network with their neighbors in which the N−H groups in the backbone of one strand establish hydrogen bonds with the C=O groups in the backbone of the adjacent strands. In the fully extended β-strand, successive side chains point straight up, then straight down, then straight up, etc. Adjacent β-strands in a β-sheet are aligned so that their Cα atoms are adjacent and their side chains point in the same direction. Here you can see a segment of beta-sheet present in the structure of bacterial OspA protein (PDB code: 2OL6)
#molecularart ... #immolecular ... #betasheet ... #planar ... #secondarystructure ... #hydrogenbond ... #ospa ... #xray
Beta-sheet structure rendered with @proteinimaging and represented with @corelphotopaint
#molecularart ... #immolecular ... #betasheet ... #planar ... #secondarystructure ... #hydrogenbond ... #ospa ... #xray
Beta-sheet structure rendered with @proteinimaging and represented with @corelphotopaint
