User:Stephen Mills/Sandbox 4 Secondary Structure: Helices XU
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< User:Stephen Mills(Difference between revisions)
(New page: '''Bold text'''==The α-helix== α-helices are the most common type of regular helix found in proteins. They are characterized by the following helix parameters: ::Dihedral angles: Φ ~ -...) |
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α-helices are the most common type of regular helix found in proteins. They are characterized by the following helix parameters: | α-helices are the most common type of regular helix found in proteins. They are characterized by the following helix parameters: | ||
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The helix shown below is a 19 amino acid chain in α-helical conformation. | The helix shown below is a 19 amino acid chain in α-helical conformation. | ||
| - | <Structure load=' | + | <Structure load='Tut_alpha_helix_XU.pdb' size='500' frame='true' align='left' caption='' scene='71/711023/Initial_alpha_helix/1' /> |
All the atoms are shown in this initial orientation (C = green; N = blue; O = red; S = yellow; H = white). The helix axis runs vertically, approximately parallel to the plane of the screen.<br/> | All the atoms are shown in this initial orientation (C = green; N = blue; O = red; S = yellow; H = white). The helix axis runs vertically, approximately parallel to the plane of the screen.<br/> | ||
| - | <Structure load='' size='350' frame='true' align='right' caption='Insert caption here' scene='Insert optional scene name here' /> | ||
Current revision
The α-helix
α-helices are the most common type of regular helix found in proteins. They are characterized by the following helix parameters:
- Dihedral angles: Φ ~ -60o, φ ~ -45o
- Repeat (number of residues per turn) = 3.6
- Rise (translation along axis per amino acid residue) = 1.5 Angstroms (0.15 nm)
- Twist (rotation around axis per amino acid residue) = 100o (= 360o/repeat)
- Pitch (translation along axis per turn) = 5.4 Angstroms (= 0.54 nm = Repeat x Rise)
The helix shown below is a 19 amino acid chain in α-helical conformation.
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All the atoms are shown in this initial orientation (C = green; N = blue; O = red; S = yellow; H = white). The helix axis runs vertically, approximately parallel to the plane of the screen.
