Beta sheet

The β sheet (also β-pleated sheet) is the second form of regular secondary structure in proteins. Beta sheets consist of beta strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet. A beta strand (also β strand) is a stretch of polypeptide chain typically 3 to 10 amino acids long with backbone in an extended conformation. The higher-level association of β sheets has been implicated in formation of the protein aggregates and fibrils observed in many human diseases, notably the amyloidoses such as Alzheimer's disease.

History

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.

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Handle

by: Potshot

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Anything dont help me
Nothing can make me feel OK
Dont wanna apologize
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Or Talk to people I don't care
Don't handle me
Just want to live it up
All that I wish is not
Much but just to say
I love you so
Just leave leave me be
(You) do what you want
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(I) wont stand the pace
(I) have no faith and no proof
Don't try to handle me
Just want to laugh
All I wish to say is that




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