Comparison of general structural properties associated with phosphorylated (pos.) vs. non-phosphorylated (neg.) residues. Serine: left column, threonine: middle column, tyrosine: right column. Annotations were taken from PDBFINDER . (a) Side chain accessibility to solvent relative to the large possible accessibility for serine. (b) Re-scaled crystallographic B-factors describe the attenuation of x-ray scattering caused by thermal motion or quenched disorder and is applicable measure for local structural rigidity. B-Factors from PDB-structures in the range of [10, 40] are mapped to the range  by PDBFINDER; 0 signifying rigid structures, 9 – indicating unresolved, rather flexible structural regions. (c) DSSP secondary structure association. B = residue in isolated beta-bridge; C = Loop, irregular stretches; E = extended strand, participates in beta ladder; G = 3-helix (3/10 helix); H = alpha helix; S = bend; T = hydrogen bonded turn.