Data from: Identification of allosteric disulphides from labile bonds in X-ray structures

Protein disulphide bonds link pairs of cysteine sulphur atoms and are either structural or functional motifs. The allosteric disulphides control the function of the protein in which they reside when cleaved or formed. Here we identify potential allosteric disulphides in all Protein Data Bank X-ray structures from bonds that are present in some molecules of a protein crystal but absent in others, or present in some structures of a protein but absent in others. We reasoned that the labile nature of these disulphides signifies a propensity for cleavage and so possible allosteric regulation of the protein in which the bond resides. A total of 511 labile disulphide bonds were identified. The labile disulphides are more stressed that the average bond, being characterised by high average torsional strain and stretching of the sulphur-sulphur bond and neighbouring bond angles. This prestress likely underpins their susceptibility to cleavage. The coagulation, complement and oxygen-sensing HIF-1 pathways, which are known or have been suggested to be regulated by allosteric disulphides, are enriched in proteins containing labile disulphides. The identification of labile disulphide bonds will facilitate the study of this post-translational modification.