Thermophilic organisms flourish in varied high-temperature environmental niches that are deadly to other organisms. Recently, genomic evidence has implicated a critical role for disulfide bonds in the structural stabilization of intracellular proteins from certain of these organisms, contrary to the conventional view that structural disulfide bonds are exclusively extracellular. Here both compu...

Heat treatment of milk causes the heat-denaturable whey proteins to aggregate with kappa-casein (kappa-CN) via thiol-disulfide bond interchange reactions. The particular disulfide bonds that are important in the aggregates are uncertain, although Cys(121) of beta-lactoglobulin (beta-LG) has been implicated. The reaction at 60 degrees C between beta-LG A and an activated kappa-CN formed small di...

The growth hormone (GH) receptor (GHR) binds GH in its extracellular domain and transduces activating signals via its cytoplasmic domain. Both GH-induced GHR dimerization and JAK2 tyrosine kinase activation are critical in initiation of GH signaling. We previously described a rapid GH-induced disulfide linkage of GHRs in human IM-9 cells. In this study, three GH-induced phenomena (GHR dimerizat...

Thiol-disulfide oxidoreductase systems of bacterial cytoplasm and eukaryotic cytosol favor reducing conditions and protein thiol groups, while bacterial periplasm and eukaryotic endoplasmatic reticulum provide oxidizing conditions and a machinery for disulfide bond formation in the secretory pathway. Oxidoreductases of the thioredoxin fold superfamily catalyze steps in oxidative protein folding...

We have examined the role of thiol-disulfide exchange reactions during the penetration of cells by Sindbis virus. The protein-protein association that form the rigid icosahedral lattice of the Sindbis virus envelope have been shown to be stabilized by disulfide bridges, and reduction of these critical disulfide bridges during cell penetration may be the mechanism by which the rigid protein latt...

It has been shown previously by our group and others that a series of four disulfide benzamides with cellular anti-human immunodeficiency virus (HIV) activity can eject zinc from HIV type 1 nucleocapsid protein (NCp7) in vitro while analogs without antiviral activity do not. We also found that the zinc ejection activity correlates with the loss of the ability of NCp7 to bind to HIV psi RNA in v...

In some earlier work on insulin (1, 2) we have shown that the sulfur of insulin existed mainly if not entirely in the disulfide form, and further that the major portion of the disulfide content could be accounted for by cystine. In continuation of this study of the sulfur of insulin we felt it would be worth while to study the behavior of the reduced or sulfhydryl form of insulin. If the disulf...

DsbA and DsbB are responsible for disulfide bond formation. DsbA is the direct donor of disulfides, and DsbB oxidizes DsbA. DsbB has the unique ability to generate disulfides by quinone reduction. It is thought that DsbB oxidizes DsbA via thiol disulfide exchange. In this mechanism, a disulfide is formed across the N-terminal pair of cysteines (Cys-41/Cys-44) in DsbB by quinone reduction. This ...

The structures of two species of potato carboxypeptidase inhibitor with nonnative disulfide bonds were determined by molecular dynamics simulations in explicit solvent using disulfide bond constraints that have been shown to work for the native species. Ten structures were determined; five for scrambled A (disulfide bonds between Cys8-Cys27, Cys12-Cys18, and Cys24-Cys34) and five for the scramb...

The SH2 domain of the C-terminal Src kinase [Csk] contains a unique disulfide bond that is not present in other known SH2 domains. To investigate whether this unusual disulfide bond serves a novel function, the effects of disulfide bond formation on catalytic activity of the full-length protein and on the structure of the SH2 domain were investigated. The kinase activity of full-length Csk decr...