Schematic of the Ramachandran plot. (A) original steric map of glycine, in standard (left) and shifted (right) coordinates; (B) revised schematic of glycine, in standard (left) and shifted (right) coordinates; (C) pre-proline. The clustered regions are: grey – sterically allowed; red – α and αL; yellow – βS; blue – βP and βPR; purple – ζ. See text for explanation of the regions.
Ho and Brasseur BMC Structural Biology 2005 5:14 doi:10.1186/1472-6807-5-14