scholarly journals Electrostatic interactions contribute to the control of intramolecular thiol–disulfide isomerization in a protein

2021 ◽  
Author(s):  
Denis Maag ◽  
Marina Putzu ◽  
Claudia Leticia Gómez-Flores ◽  
Frauke Gräter ◽  
Marcus Elstner ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Electrostatic Interactions ◽  
Structural Factors ◽  
Exchange Reactions ◽  
Disulfide Exchange ◽  
Immunoglobulin Domain ◽  
Disulfide Isomerization

The roles of structural factors and of electrostatic interactions with the environment on the outcome of thiol–disulfide exchange reactions were investigated in a mutated immunoglobulin domain (I27*) under mechanical stress....

scholarly journals Mitochondrial Thioredoxin-Glutathione Reductase from LarvalTaenia crassiceps(Cysticerci)

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Alberto Guevara-Flores ◽  
Irene P. del Arenal ◽  
Guillermo Mendoza-Hernández ◽  
Juan Pablo Pardo ◽  
Oscar Flores-Herrera ◽  
...  
Keyword(s):  
Glutathione Reductase ◽  
Reductase Activity ◽  
Catalytic Efficiency ◽  
Dependent Manner ◽  
Exchange Reactions ◽  
Disulfide Exchange ◽  
Oxidative Inactivation ◽  
Disulfide Reductase ◽  
Thioredoxin Peroxidase ◽  
Thioredoxin Glutathione Reductase

Mitochondrial thioredoxin-glutathione reductase was purified from larvalTaenia crassiceps(cysticerci). The preparation showed NADPH-dependent reductase activity with either thioredoxin or GSSG, and was able to perform thiol/disulfide exchange reactions. At25∘Cspecific activities were437  ±  27mU mg-1and840  ±  49mU mg-1with thioredoxin and GSSG, respectively. ApparentKmvalues were0.87  ±  0.04 μM,41  ±  6 μM and19  ±  10 μM for thioredoxin, GSSG and NADPH, respectively. Thioredoxin from eukaryotic sources was accepted as substrate. The enzyme reduced H2O2in a NADPH-dependent manner, although with low catalytic efficiency. In the presence of thioredoxin, mitochondrial TGR showed a thioredoxin peroxidase-like activity. All disulfide reductase activities were inhibited by auranofin, suggesting mTGR is dependent on selenocysteine. The reductase activity with GSSG showed a higher dependence on temperature as compared with the DTNB reductase activity. The variation of the GSSG- and DTNB reductase activities on pH was dependent on the disulfide substrate. Like the cytosolic isoform, mTGR showed a hysteretic kinetic behavior at moderate or high GSSG concentrations, but it was less sensitive to calcium. The enzyme was able to protect glutamine synthetase from oxidative inactivation, suggesting that mTGR is competent to contend with oxidative stress.

scholarly journals ATP and Tri-Polyphosphate (TPP) Suppress Protein Aggregate Growth by a Supercharging Mechanism

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1646
Author(s):  
Jordan Bye ◽  
Kiah Murray ◽  
Robin Curtis
Keyword(s):  
Protein Interactions ◽  
Electrostatic Interactions ◽  
Colloidal Stability ◽  
Conformational Stability ◽  
Kinetic Studies ◽  
Structural Factors ◽  
Protein Protein Interactions ◽  
Protein Aggregate ◽  
Aggregate Growth

A common strategy to increase aggregation resistance is through rational mutagenesis to supercharge proteins, which leads to high colloidal stability, but often has the undesirable effect of lowering conformational stability. We show this trade-off can be overcome by using small multivalent polyphosphate ions, adenosine triphosphate (ATP) and tripolyphosphate (TPP) as excipients. These ions are equally effective at suppressing aggregation of ovalbumin and bovine serum albumin (BSA) upon thermal stress as monitored by dynamic and static light scattering. Monomer loss kinetic studies, combined with measurements of native state protein–protein interactions and ζ-potentials, indicate the ions reduce aggregate growth by increasing the protein colloidal stability through binding and overcharging the protein. Out of three additional proteins studied, ribonuclease A (RNaseA), α-chymotrypsinogen (α-Cgn), and lysozyme, we only observed a reduction in aggregate growth for RNaseA, although overcharging by the poly-phosphate ions still occurs for lysozyme and α-Cgn. Because the salts do not alter protein conformational stability, using them as excipients could be a promising strategy for stabilizing biopharmaceuticals once the protein structural factors that determine whether multivalent ion binding will increase colloidal stability are better elucidated. Our findings also have biological implications. Recently, it has been proposed that ATP also plays an important role in maintaining intracellular biological condensates and preventing protein aggregation in densely packed cellular environments. We expect electrostatic interactions are a significant factor in determining the stabilizing ability of ATP towards maintaining proteins in non-dispersed states in vivo.

Self-Healing Polymer Films Based on Thiol–Disulfide Exchange Reactions and Self-Healing Kinetics Measured Using Atomic Force Microscopy

2011 ◽  
Vol 45 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Jeong Ae Yoon ◽  
Jun Kamada ◽  
Kaloian Koynov ◽  
Jake Mohin ◽  
Renaud Nicolaÿ ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Polymer Films ◽  
Self Healing ◽  
Exchange Reactions ◽  
Force Microscopy ◽  
Disulfide Exchange ◽  
Atomic Force

scholarly journals Reactions of Organic Disulfides and Gold(I) Complexes

1999 ◽  
Vol 6 (4-5) ◽  
pp. 247-253 ◽  
Author(s):  
Melanie DiLorenzo ◽  
Shantheni Ganesh ◽  
Lily Tadayon ◽  
Jinhua Chen ◽  
Mitchell R. M. Bruce ◽  
...  
Keyword(s):  
Exchange Reaction ◽  
Chemical Reactivity ◽  
Conductivity Measurements ◽  
Exchange Reactions ◽  
Disulfide Exchange ◽  
First Order ◽  
Mixed Disulfide ◽  
Ionic Mechanisms ◽  
Thiolate Complexes ◽  
Gold Thiolate

Gold-thiolate/disulfide exchange reactions of (p-SC6H4Cl)2 with Ph3PAu(SC6H4CH3) , dppm(AuSC6H4CH3)2, and dppe(AuSC6H4CH3)2 were investigated. The rate of reactivity of the gold-thiolate complexes with (p-SC6H4Cl)2 is: dppm(AuSC6H4CH3)2>> dppe(AuSC6H4CH3)2>Ph3PAu(SC6H4CH3). This order correlates with conductivity measurements and two ionic mechanisms have been evaluated. H1 NMR experiments demonstrate that in the reaction of dppm(AuSC6H4CH3)2 with (p-SC6H4Cl)2, the mixed disulfide, ClC6H4SSC6H4CH3, forms first, followed by the formation of (p-SC6H4CH3)2. The rate law is first order in (pp-SC6H4Cl)2 and partial order in dppm(AuSC6H4CH3)2. Results from electrochemical and chemical reactivity studies suggest that free thiolate is not involved in the gold-thiolate/disulfide exchange reaction. A more likely source of ions is the dissociation of a proton from the methylene backbone of the dppm ligand which has been shown to exchange with D2O. The implications of this are discussed in terms of a possible mechanism for the gold-thiolate/disulfide exchange reaction.

scholarly journals Conferring specificity in redox pathways by enzymatic thiol/disulfide exchange reactions

2016 ◽  
Vol 50 (2) ◽  
pp. 206-245 ◽  
Author(s):  
Luis Eduardo S. Netto ◽  
Marcos Antonio de Oliveira ◽  
Carlos A. Tairum ◽  
José Freire da Silva Neto
Keyword(s):  
Exchange Reactions ◽  
Disulfide Exchange
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