Ramachandran plot (protein phi vs psi backbone dihedral angles) for Glycine residues, wich have only an H atom as side chain and are therefore less conformationally limited than the general case for amino acids with Cbeta or longer side chains.  Data from 500 proteins at 1.7Å resolution or better, as reported in Lovell et al, 2003 Proteins 50:437.
Dcrjsr
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<span class="int-own-work" lang="en">Own work</span>