Regarding convention for dihedral angle

[Sanjeet Singh]

Hello all,

I am computing the dihedral angle of a polymer using the following module in MDAnalysis:

from MDAnalysis.lib.distances import calc_dihedrals

I would like to know about the different ranges of dihedral angles corresponding to different conformations such as cis, trans, gauche_plus and gauche_minus.

I would be grateful for any suggestions.

Thank you,

Sanjeet

[Hugo Macdermott-Opeskin]

Hi Sanjeet, 

MDAnalysis returns dihedrals in terms of angles. You can then compare these to the definitions of gauche etc in this article: https://en.wikipedia.org/wiki/Dihedral_angle
Note that cis and trans are actually a seperate concept, you are looking for syn and anti. 

Cheers, 

Hugo