Difference between revisions of "Torsion angle"
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[[Sidechain]]s can also contain torsion angles, they are indicated as [[chi-angle]]s. | [[Sidechain]]s can also contain torsion angles, they are indicated as [[chi-angle]]s. | ||
− | [Image:Camera.gif|40px|link=http://www.cmbi.ru.nl/~hvensela/VIDEO/torsion_angle.mp4|movie]] Prof. Vriend explains torsion angles in this movie. [http://www.cmbi.ru.nl/~hvensela/VIDEO/torsion_angle.mp4] | + | [[Image:Camera.gif|40px|link=http://www.cmbi.ru.nl/~hvensela/VIDEO/torsion_angle.mp4|movie]] Prof. Vriend explains torsion angles in this movie. [http://www.cmbi.ru.nl/~hvensela/VIDEO/torsion_angle.mp4] |
Revision as of 13:41, 12 April 2010
The angle between two bonds
A torsion angle, also known as a dihedral angle, is formed by three consecutive bonds in a molecule and defined by the angle created between the two outer bonds. The backbone of a protein has three different torsion angles.
- The phi-angle (φ) - around the N-Cα bond
- The psi-angle (ψ) - around the Cα-C bond
- The omega-angle (ω) - around the peptide bond between C and N.
The ω-bond has a slightly double bond character and is therefore almost always 180 degrees. The structure of a protein is mainly formed by the φ- and ψ-angles.
Every secondary structure element forces the backbone into a specific range of torsion angles, this can be visualized in a ramachandran plot.
The figure shows the location of the φ, ψ and ω-angles
Sidechains can also contain torsion angles, they are indicated as chi-angles.
Prof. Vriend explains torsion angles in this movie. [1]