Fig. 3.

Analysis of primary sequence, distribution in secondary structures, and surface accessibility of S-nitrosylated cysteine residues. (A) The frequency of S-nitrosocysteine (n = 142; black bars) and unmodified cysteine residues (n = 473; white bars) within the same proteins in different secondary structures was calculated using the available crystal structures. (B) Distribution of residues flanking S-nitrosylated cysteines in secondary structures. SNO-cysteines are located at position 0 and the frequency for 10 residues upstream (−10) and 10 residues downstream (+10) was calculated as described earlier. (C) Quantile–quantile plot of relative RSA for S-nitrosylated (x axis) versus unmodified (y axis) cysteine residues. RSA values were calculated from the biological assemblies defined by PISA (42) for available crystal structures. (D) Top three scoring sequence motifs for residues flanking S-nitrosylated cysteine residue. Note the presence of charged as well as aliphatic amino acids able to “accommodate” protein and small-molecule binding. (E) Top two sequence motifs assigned to the residues sensitive to Trx system.