RamPlot: a webserver to draw 2D, 3D and assorted Ramachandran (ϕ, ψ) maps

The Ramachandran steric map of torsion angles (ϕ, ψ) introduced in 1963 has been widely used for protein structure validation and model building. Many developments in the field have made it essential to develop a utility to plot assorted types of maps for the following specific reasons: (i) to investigate different types (Gly, Val/Ile, pre/trans/cis-Pro and general) of 2D and 3D maps, addressing the diverse steric environments and frequency distribution of conformations, (ii) to examine polypeptides containing non-standard residues, (iii) for better visualization and analysis of conformational excursions and transitions in simulation, and (iv) to analyse torsion angles across three rotatable bonds such as preferred backbone-dependent rotamers. The utility RamPlot is accessible online (https://www.ramplot.in) and offline (via GitHub, https://github.com/mayank2801/ramplot and PyPI repository). It serves as a unique tool to draw and interpret a great variety of Ramachandran maps for natural and non-standard residues, which is otherwise unfeasible using existing tools and servers.