Pi helix

The π -helix is in nature very rarely occurring secondary structure of proteins. In comparison to the α -helix ubiquitous which requires an average of 3.6 amino acids per turn, are at the 4,4 π -helix amino acids. Thus, the π - helix is ​​energetically less stable than the α - helix. In proteins, one occasionally finds α -helices, at the end followed by a rotation of π - helix. Longer π -helices are not found. The structure of the π -helix was discovered by Linus Pauling.

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