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Topic: Disulfide bond

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In the News (Fri 19 Jul 19)

  Disulfide bond - Wikipedia, the free encyclopedia
Disulfide bonds in proteins are formed between the thiol groups of cysteine residues.
The prototype of a protein disulfide bond is the two-amino-acid peptide, cystine, which is composed of two cysteine amino acids joined by a disulfide bond (shown in Figure 2 in its unionized form).
Disulfide bonds play an important protective role for bacteria as a reversible switch that turns a protein on or off when bacterial cells are exposed to oxidation reactions.
en.wikipedia.org /wiki/Disulfide_bond   (1248 words)

 Disulfide - Wikipedia, the free encyclopedia
In chemistry, a disulfide ion is an anion (negatively-charged ion) formed by two sulfur atoms having an overall -2 charge.
In many cases, each of the two sulfur atoms in a disulfide group is covalently bonded to a carbon atom in an organic compound, forming a disulfide bond, sometimes called a disulfide linkage or a disulfide bridge.
Examples of organic compounds containing a disulfide bond or group are the biological amino acid cystine and lipoic acid.
en.wikipedia.org /wiki/Disulfide   (270 words)

 UM Biophysics Faculty | James Bardwell   (Site not responding. Last check: 2007-10-13)
One indication of how vital disulfide bonds are for protein folding and stability is the fact that their reduction will often cause proteins to unfold.
Since disulfide bond formation is one of the few covalent modifications that occurs in protein folding we are in the unusual and advantageous position of being able to phrase our questions about the catalysis of a protein folding reaction in clear biochemical terms.
Isomerization of disulfide bonds is vital for the proper folding of proteins that possess multiple disulfides, including many proteins of pharmacological importance.
www.umich.edu /~biophys/facultstaff/research/bardwell.html   (656 words)

 MIT Department of Biology: Chris A. Kaiser   (Site not responding. Last check: 2007-10-13)
It has long been known that disulfide bonds form as newly synthesized proteins enter the ER although the enzymatic pathway for the formation of disulfide bonds has only recently come to light.
PDI and Ero1p are linked by a disulfide relay in which disulfide bonds formed within Ero1p are transferred to PDI, which in turn transfers disulfide bonds to substrate proteins.
We believe that this disulfide shuttle mechanism is crucial for the ability of both Ero1p and Erv2p to transfer disulfides specifically to PDI rather than to other free thiols in the ER such as glutathione.
web.mit.edu /biology/www/facultyareas/facresearch/kaiser.shtml   (1097 words)

 Disulfide bond   (Site not responding. Last check: 2007-10-13)
Disulfide bonds play an imporant protective role for bacteria as a reversible switch that turns a protein on or off When bacterial cells are exposed to Oxidation reactions.
Disulfide bonds also play a significant role in the vulcanization of rubber.
In eukaryotic cells, disulfide bonds are formed in the lumen of the RER (rough endoplasmic reticulum) but not in the cytosol.
disulfide-bond.iqnaut.net   (430 words)

 Assignment of disulfide bond connectivity is possible in proteins containing adjacent cysteines by using ...
Assignment of disulfide bond connectivity is possible in proteins containing adjacent cysteines by using cyanylation/cleavage/mass mapping.
Conventional methodology for determining the connectivity of disulfide bonds in proteins relies on controlled proteolysis to cleave the peptide backbone in between the cysteine residues.
When this disulfide bond was reduced, free sulfhydryls at residues 19 and 61 were available for cyanylation which rendered them susceptible to cleavage as illustrated in the middle of the chemical scheme.
www.msu.edu /user/massspec/asms98/JTW/ASMS-JTW.htm   (571 words)

 Disulfide Bond Configuration of Human Cytomegalovirus Glycoprotein B -- Lopper and Compton 76 (12): 6073 -- The Journal ...
The disulfide bond configurations of both HSV-2 gB and CMV gB are indicated by solid lines connecting appropriate cysteine pairs.
The similarity of disulfide bonding reflects the high conservation of cysteine residues between these two glycoproteins although significant differences exist in the region from C185 to C250 of CMV gB.
Disulfide bond structure of glycoprotein D of herpes simplex virus types 1 and 2.
jvi.asm.org /cgi/content/full/76/12/6073   (5014 words)

 Disulfide Bond Exchange in Rhodopsin
Rhodopsin contains two cysteines (Cys110 and Cys187) that are highly conserved among members of the G protein coupled receptor family and that form a disulfide bond connecting helixes 3 and 4 on the extracellular side of the protein.
We show here that the inability to observe the disulfide bond on SDS gels is the result of a disulfide bond exchange reaction which occurs when this split rhodopsin is denatured in preparation for SDS-PAGE.
Cys185 reacts with the native disulfide, displacing Cys110 and forming a new disulfide with Cys187.
pubs.acs.org /cgi-bin/jtext?bichaw/37/i05/abs/bi9721445   (246 words)

 Disulfide Bonds   (Site not responding. Last check: 2007-10-13)
Disulfide bonds are formed by the oxidation of thiol (-SH) groups in cysteine residues:
Disulfide bonds occur intramolecularly (i.e within a single polypeptide chain) and intermolecularly (i.e.
Intramolecular disulfide bonds stabilize the tertiary structures of proteins while thoise that occur intermolecularly are involved in stabilizing quartenary structure.
webhost.bridgew.edu /fgorga/proteins/disulfide.htm   (103 words)

 James C.A. Bardwell
The formation of disulfide bonds is vital for the proper folding of most secreted proteins, including many of medical importance.
DsbA, therefore, is essential for disulfide bond formation in endogenous Escherichia coli proteins, many virulence factors, and in eukaryotic proteins expressed in E.
Our in vitro reconstitution of the disulfide bond catalytic system established where the oxidative power for protein folding originates and how this vital step in the catalysis of protein folding is linked to cellular metabolism (see figure).
www.hhmi.org /research/investigators/bardwell.html   (551 words)

 Effect of the intermolecular disulfide bond on the conformation and stability of glial cell line-derived neurotrophic ...
Effect of the intermolecular disulfide bond on the conformation and stability of glial cell line-derived neurotrophic factor -- Li et al.
Effect of the intermolecular disulfide bond on the conformation and stability of glial cell line-derived neurotrophic factor
in the absence of the interchain disulfide bond.
peds.oxfordjournals.org /cgi/content/full/15/1/59   (3243 words)

 Trapping and Identification of Folding Intermediates by Mass Spectrometry
For those intermediates containing more than one disulfide bond, partial reduction of the trapped intermediate followed by additional cyanylation, cleavage, and mass-mapping of the fragments allows one to deduce the pairing of the disulfide bonds in the intermediate in most cases.
Under alkaline conditions, the cleavage of the peptide bond occurs on the N-terminal side of cyanylated cysteines to form truncated peptides which after reduction of the remaining disulfide bonds can be mass mapped by desorption ionization mass spectrometry (8).
Exposing a second aliquot of the 2-disulfide bond intermediate to partial reduction, further cyanylation, and then cleavage allows recognition of the connectivity of the disulfide bonds present in the intermediate.
www.abrf.org /JBT/Articles/JBT0014/JBT0014.html   (2694 words)

 Retrovirology | Full text | Evolution of the HIV-1 envelope glycoproteins with a disulfide bond between gp120 and gp41
We previously described the construction of a soluble Env variant that is stabilized by the introduction of an intermolecular disulfide bond between gp120 and the gp41 ectodomain (gp41e) [9,10].
Stabilization of the native Env complex by disulfide bond linkage is likely to impose constraints on Env function because a certain degree of flexibility is probably essential for Env to undergo the conformational changes that eventually lead to fusion of the viral and cellular membranes.
The presence of a disulfide bond between the SU and TM subunits of other viruses, including retroviruses, provides a rationale for this study [23-40].
www.retrovirology.com /content/1/1/3   (5567 words)

 The prokaryotic enzyme DsbB may share key structural features with eukaryotic disulfide bond forming oxidoreductases -- ...
Two pairs of conserved cysteines are required for the oxidative activity of Ero1p in protein disulfide bond formation in the endoplasmic reticulum.
Gross, E., Kastner, D.B., Kaiser, C.A., and Fass, D. Structure of Ero1p, source of disulfide bonds for oxidative protein folding in the cell.
Guilhot, C., Jander, G., Martin, N.L., and Beckwith, J. Evidence that the pathway of disulfide bond formation in Escherichia coli involves interactions between the cysteines of DsbB and DsbA.
protsci.highwire.org /cgi/content/full/14/6/1630   (5715 words)

 Protein disulfide isomerase
PDI (EC was first identified as a catalyst of native disulfide bond formation 40 years ago, when Anfinsen and his group studied which components in rat liver lysates enhanced the rate of reactivation of reduced ribonuclease.
The complexity of these processes involving reduction, oxidation and isomerization of disulfide bonds, the variety of catalysts known in eukaryotic cells and the recent discovery of multiple different pathways for disulfide bond formation have hindered the progression of a clear understanding of actual physiological events.
A schematic representation of the mechanisms of catalysis of reduction, oxidation and isomerization of disulfide bonds by PDI is presented in Figure 3.
herkules.oulu.fi /isbn9514271726/html/x197.html   (4951 words)

 Overexpression of Protein Disulfide Isomerase DsbC Stabilizes Multiple-Disulfide-Bonded Recombinant Protein Produced ...
Eukaryotic protein disulfide isomerase complements Escherichia coli dsbA mutants and increases in the yield of a heterologous secreted protein with disulfide bonds.
An in vivo pathway for disulfide bond isomerization in Escherichia coli.
Reduction of the periplasmic disulfide bond isomerase, DsbC, occurs by passage of electrons from cytoplasmic thioredoxin.
aem.asm.org /cgi/content/full/66/9/3960   (3816 words)

 In Vivo Protein Folding
For example, the folding of many important therapeutic proteins hinges on the formation of disulfide bonds, an enzymatically catalyzed process that is not very efficient in bacteria.
In the course of these studies we are using genetic approaches to identify the rate limiting steps in disulfide bond formation and, more specifically, in the isomerization of mismatched disulfide bonds.
In other studies, in collaboration with the Beckwith lab (Harvard), we are exploring ways to engineer the redox state of the cellular cytoplasm and thus aid the formation of disulfide bonds.
www.che.utexas.edu /georgiou/Research/In_Vivo_Protein_Folding.htm   (712 words)

 Two Pairs of Conserved Cysteines Are Required for the Oxidative Activity of Ero1p in Protein Disulfide Bond Formation ...
The formation of native protein disulfide bonds is a critical step in the folding of many secretory proteins.
Ero1p-Pdi1p mixed disulfides were isolated by modifying free thiols with NEM prior to immunoprecipitation with anti-myc antibody under nonreducing but denaturing conditions.
Frand, A.R., Cuozzo, J., and Kaiser, C.A. Pathways for protein disulfide bond formation in the endoplasmic reticulum.
www.molbiolcell.org /cgi/content/full/11/9/2833   (6707 words)

 Disulfide Bond Mutations in Follicle-Stimulating Hormone Result in Uncoupling of Biological Activity from Intracellular ...
Disulfide Bond Mutations in Follicle-Stimulating Hormone Result in Uncoupling of Biological Activity from Intracellular Behavior -- Hiro’oka et al.
and cys 34–88 is a bond in the cystine knot.
The disulfide bond 34–88 in the cystine knot corresponds to disulfide bond 28–82 in the FSHß-subunit.
endo.endojournals.org /cgi/content/full/141/12/4751   (3442 words)

 Disulfide bond   (Site not responding. Last check: 2007-10-13)
An intramolecular disulfide bond serves as a reversible switch to turn on or off a protein that helps protect bacterial cells from damaging oxidation reactions.
Researchers have shown that high levels of H2O2 trigger formation of a disulfide bond between two specific cysteine residues of OxyR.
A reaction that usually inactivates cytoplasmic proteins -- the oxidation of cysteines to form intramolecular disulfides -- has been exploited as an on-off switch.
classweb.gmu.edu /sslayden/proteins/protein-structure/disulfide.htm   (98 words)

 Role of Native-State Topology in the Stabilization of Intracellular Antibodies -- Settanni et al. 81 (5): 2935 -- ...
of the cytoplasm, the role of the disulfide bond, and the behavior
and is supposed to mimic the peptide bond and the geometrical
The role of the intrachain disulfide bond in the conformation and stability of the constant fragment of the immunoglobulin light chain.
www.biophysj.org /cgi/content/full/81/5/2935   (5890 words)

 FOCUS - February 6, 2004 - MICROBIOLOGY: Early Step in Protein-folding Revealed by Bacterial Mutant
Normally, DsbA and the protein dissociate too quickly for the intermediate form, or mixed disulfide bond, to be observed.
What is more, they were able to show that the binding occurs via disulfide bonds that are then transferred to the protein substrate.
"Disulfide bonds are present in a lot of important proteins, like insulin, antibodies, hormones, and membrane receptors," Beckwith said.
focus.hms.harvard.edu /2004/Feb6_2004/microbiology.html   (1064 words)

 disulfide Articles - TextMed
Disulfide bond formation in the refolding of thermophilic fungal...
Role of the hexapeptide disulfide loop in the gamma-carboxyglutamic...
Role of disulfide bridges in the activity and stability...
www.textmed.com /chemical/disulfide-articles.htm   (471 words)

 Disulfide bond formation in the endoplasmic reticulum
Since any two cysteines have the potential to form a disulphide bond, the formation of native disulphide bonds in the ER is a complex process and is the rate-limiting step in the biogenesis of many secreted or outer membrane proteins.
The majority of proteins thought to be involved in disulphide bond formation in the ER belong to the protein disulphide isomerase (PDI) family and hence an understanding of the mechanisms of action of the PDI family is critical for our understanding of native disulphide bond formation.
The mechanism of action of PDI as a catalyst of native disulphide bond formation in folding polypeptides depends on the ability to catalyse disulphide-dithiol exchange, to bind non-native proteins and to trigger conformational changes in the bound substrate, allowing access to buried cysteine residues.
www.biocenter.oulu.fi /projects/ruddock.html   (1707 words)

 Mutationally Induced Disulfide Bond Formation within the Third Extracellular Loop Causes Melanocortin 4 Receptor ...
disulfide bond was able to restore normal receptor potency.
B, to analyze the effect of disulfide bridge-reducing agents, transfected cells were washed 1 h prior to stimulation and were incubated in the presence or absence of 10 m
It was speculated that this disulfide bond in the MC1R
www.jbc.org /cgi/content/full/278/49/48666   (4398 words)

 Analytical Chemistry Faculty at Michigan State University
Classical approaches to disulfide bond mapping involve the use of proteases which require a cleavage site in between the cysteines, a constraint that becomes quite serious as the cysteines lie close to one another, and impossible if the cysteines are adjacent in the sequence.
The J.T. Watson laboratory is currently devoted to the characterization of modifications to protein structure, in particular disulfide bond linkages and the formation of the secondary structures during the refolding of proteins.
We have found that it is possible to trap sulfhydryl-containing intermediates during the refolding of cysteine-containing proteins that involve disulfide bond formation in the native structure.
www.cem.msu.edu /~analweb/watson.html   (1003 words)

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