title: Allosteric disulfide bonds.
abstract: Disulfide bonds have been generally considered to be either structural or catalytic. Structural bonds stabilize a protein, while catalytic bonds mediate thiol-disulfide interchange reactions in substrate proteins. There is emerging evidence for a third type of disulfide bond that can control protein function by triggering a conformational change when it breaks and/or forms. These bonds can be thought of as allosteric disulfides. To better define the properties of allosteric disulfides, we have analyzed the geometry and dihedral strain of 6874 unique disulfide bonds in 2776 X-ray structures. A total of 20 types of disulfide bonds were identified in the dataset based on the sign of the five chi angles that make up the bond. The known allosteric disulfides were all contained in 1 of the 20 groups, the -RHStaple bonds. This bond group has a high mean potential energy and narrow energy distribution, which is consistent with a functional role. We suggest that the -RHStaple configuration is a hallmark of allosteric disulfides. About 1 in 15 of all structurally determined disulfides is a potential allosteric bond.
authors.affiliation: Centre for Vascular Research, University of New South Wales and Department of Haematology, Prince of Wales Hospital, Sydney, New South Wales 2052, Australia.
authors.forename: Bryan
authors.initials: B
authors.lastname: Schmidt
authors.forename: Lorraine
authors.initials: L
authors.lastname: Ho
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Hogg
mesh_terms: D000495:Allosteric Site; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds; D020124:Thermotoga maritima / Q000201:enzymology; D014961:X-Ray Diffraction
chemical_list: D004220:Disulfides; D013438:Sulfhydryl Compounds; D003545:Cysteine