Why are ? helices and ? sheets common folding patterns in polypeptides? Both of these secondary structures require more than one polypeptide chain to be able to fold into these patterns. Since all proteins contain multiple polypeptide chains, these folding patterns are common. Since R-groups are present on all amino acids, there is a nearly infinite number of ways that ? helices and ? sheets can form. As a result, over evolutionary time, these folding patterns have become common. Amino acid side chains are not involved in forming the hydrogen bonds, allowing many different sequences to adopt these folding patterns. Molecular chaperones tend to fold polypeptides into these common folding patterns.
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Step 1: Hydrogen bonding occurs between the carbonyl oxygen of one amino acid and the amide hydrogen of another amino acid in both α helices and β sheets. Show more…
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