Alpha Helix (Rotational Angle) Calculator

Posted by Dinesh on

Online biology calculator to calculate Alpha helix (rotational angle).

Alpha helix

The Alpha Helix (α-helix) is a common motif in the secondary structure of proteins and is a righthand-spiral conformation (i.e. helix) in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid located three or four residues earlier along the protein sequence.

Alpha Helix (Rotational Angle) Calculation

Formula:

3×cosΩ=1-4×cosϕ+ψ22

where,
ϕ = Dihedral angle of one residue (angle between two planes),
ψ = Dihedral angle of the next residue (angle between two planes) ,
Ω = The the rotation angle