Intra- and interchain disulfide bond generation in S100b protein.
Disulfide-bridged S100b protein formation, aircatalyzed and induced by thiol/disulfide exchange, was studied under various ionic conditions. As native, physiological disulfide-bridged proteins are obtained easily from their reduced counterparts under appropriate redox conditions, this work was performed to determine whether this was the case for disulfide-bridged S100b proteins, reported to have neurite extension activity. In nondenaturating native medium, no disulfide-bridged species could be generated from reduced proteins in any of the ion-induced conformations tested (no ions, Ca2+, Zn2+, or K+) under widely different redox conditions. Only mixed disulfides accumulated, in certain cases. In contrast, intrasubunit monomeric and intersubunit dimeric disulfide-bridged species were readily and efficiently generated under denaturating conditions. A brief characterization of these oxidized species suggested that they differed widely in structure from their reduced counterparts and that they probably did not bind Ca2+. Taken together, these data question the physiological relevance of these disulfide-bridged S100b protein species.
Mely
Y
Y
Université Louis Pasteur, Laboratoire de Biophysique, Faculté de Pharmacie, Illkirch, France.
Gérard
D
D
D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002850:Chromatography, Gel; D004220:Disulfides; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D009414:Nerve Growth Factors; D010084:Oxidation-Reduction; D011485:Protein Binding; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000302:isolation & purification / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000032:analysis
D002135:Calcium-Binding Proteins; D004220:Disulfides; D046911:Macromolecular Substances; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D013438:Sulfhydryl Compounds; D002118:Calcium