Protein folding -4

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. A refined version was proposed by Linus Pauling and Robert Corey in 1951. Their model incorporated the planarity of the peptide bond which they previously explained as resulting from keto-enol tautomerization. #proteinFolding #polypeptide #peptide #bioinformatics #betaSheets #protein3d #parallelBetaSheets #antiparallelBetaSheets #NikolaysGeneticsLessons #protein #aminoAcid #disulfideBridges #covalentBounding #ionicBounding #hydrophobicInteraction #proteinStructure #proteinSequence #aminoAcids #proteins #Polypeptides #ImidazolRing #Histidine #polypeptideChain #hydrolysesSynthesis #condensationReaction