Alpha Helix (Rotational Angle) Calculator

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

Formula:

$3×\mathrm{cos}\left(\Omega \right)=1-4×\mathrm{cos}{\left(\frac{\varphi +\psi }{2}\right)}^{2}$

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