The Dissociation of Proteins by Chaotropic Salts

Sawyer, William H.; Puckridge, Jonathan

doi:10.1016/s0021-9258(19)43151-7

Cited by 97 publications

(23 citation statements)

References 36 publications

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“…There are alternatives to the chaotropic theory that are not subject to the same criticism; for instance, the dissociation of a protein multimer may be due to preferential binding of the ions to the protomers rather than the muhimer (Aune, Goldsmith, and Timasheff, 1971). The theory of preferential binding was shown by Sawyer and Puckridge (1973) to explain the dissociation of the octamer of 13-1actoglobulin by NaSCN and other salts. It is interesting that the preferential binding theory leads to a similar order of potency of ions as the chaotropic theory, especially when the dissociation of protein multimers involves breaking of hydrogen bonds (as is the case for [3-1actoglobulin; Sawyer and Puckridge, 1973).…”

Section: The Mechanism Of Action Of Perchloratementioning

confidence: 99%

“…The theory of preferential binding was shown by Sawyer and Puckridge (1973) to explain the dissociation of the octamer of 13-1actoglobulin by NaSCN and other salts. It is interesting that the preferential binding theory leads to a similar order of potency of ions as the chaotropic theory, especially when the dissociation of protein multimers involves breaking of hydrogen bonds (as is the case for [3-1actoglobulin; Sawyer and Puckridge, 1973).…”

Section: The Mechanism Of Action Of Perchloratementioning

confidence: 99%

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Perchlorate enhances transmission in skeletal muscle excitation-contraction coupling.

Gonzalez

Rı́os

1993

The Journal of General Physiology

100

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A B S T R A C T The effects of the anion perchlorate (present extracellularly at 8 raM)were studied on functional skeletal muscle fibers from Rana pipiens, voltage-clamped in a Vaseline gap chamber. Established methods were used to monitor intramembranous charge movement and flux of Ca release from the sarcoplasmic reticulum (SR) during pulse depolarization. Saponin permeabilization of the end portions of the fiber segment (Irving, M., J. Maylie, N. L. Sizto, and W. K. Chandler. 1987. Journal of General Physiology. 89:1--41) substantially reduced the amount of charge moving during conventional control pulses, thus minimizing a technical error that plagued our previous studies. Perchlorate prolonged the ON time course of charge movement, especially at low and intermediate voltages. The OFFs were also made slower, the time constant increasing twofold. The hump kinetic component was exaggerated by CIO 4 or was made to appear in fibers that did not have it in reference conditions. CIO 4 had essentially no kinetic ON effects at high voltages (>_ 10 mV). C10~ changed the voltage distribution of mobile charge. In single Boltzmann fits, the midpoint potential P was shifted -20 mV and the steepness parameter K was reduced by 4.7 mV (or 1.78-fold), but the maximum charge was unchanged (n = 9). Total Ca content in the SR, estimated using the method of Schneider et al. (Schneider, M. F., B. J. Simon, and G. Szucs. 1987. Journal of Physiology. 392:167-192) for correcting for depletion, stayed constant over tens of minutes in reference conditions but decayed in CIO 4 at an average rate of 0.3 ~mol/liter myoplasmic water per s. C10 4 changed the kinetics of release flux, reducing the fractional inactivation of release after the peak. CIO 4 shifted the voltage dependence of Ca release flux. In particular, the threshold voltage for Ca release was shifted by about -20 mV, and the activation of the steady component of release flux was shifted by > 20 mV in the negative direction. The shift of release activation was greater than th]~t of mobile charge. Thus the threshold charge, defined as the minimum charge moved for eliciting a detectable Ca transient, was reduced from 6 nC/I~F (0.55, n = 7) to 3.4 (0.53). The average of the paired differences was 2.8 (0.33, P < 0.01). The effects ofC10 4 were then studied in fibers in modified functional situations. Depletion of Ca in the SR, achieved by high frequency pulsing in the presence of intracellular BAPTA and EGTA, simplified but did not eliminate the effects of CIO 4. ON humps were not observed in the depleted fibers but the slowing effect of CIO~, both in ON and OFF, was still present. The shift in P was reduced to -15 mV, the change in steepness was reduced to ~ 15%, and Qmax was unchanged. The threshold charge was reduced by CIO 4 regardless of depletion. In fibers inactivated by prolonged depolarization CIO~ did not change the kinetics of charge movement (charge 2) but changed its voltage distribution, shifting Vby -14 mV (n = 6). The CI channel blockers A9C, SITS, and DIDS shif...

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Section: The Mechanism Of Action Of Perchloratementioning

confidence: 99%

Section: The Mechanism Of Action Of Perchloratementioning

confidence: 99%

Perchlorate enhances transmission in skeletal muscle excitation-contraction coupling.

Gonzalez

Rı́os

1993

The Journal of General Physiology

100

View full text Add to dashboard Cite

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“…Life in these bittern brines must contend not only with extremely low water activity but also with chaotropicity: the disruptive effects of dissolved ions on proteins, lipid membranes and other macromolecules. Chaotropic solutes, like MgCl 2 , destabilize and denature biomolecules by disrupting hydrogen bonding and other non‐covalent molecular interactions (Sawyer and Puckridge, 1973; Duda et al ., 2004; Cray et al ., 2013; Ball and Hallsworth, 2015). Previous studies estimate that the chaotropic effects of MgCl 2 are prohibitive of life at concentrations above 2.3 M, though compensating kosmotropic (stabilizing) solutes may allow life up to 3.03 M MgCl 2 (Hallsworth et al ., 2007; Yakimov et al ., 2015).…”

Section: Introductionmentioning

confidence: 99%

Microbial diversity and activity in Southern California salterns and bitterns: analogues for remnant ocean worlds

Klempay

Arandia-Gorostidi

Dekas

et al. 2021

Environmental Microbiology

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Concurrent osmotic and chaotropic stress make MgCl 2 -rich brines extremely inhospitable environments. Understanding the limits of life in these brines is essential to the search for extraterrestrial life on contemporary and relict ocean worlds, like Mars, which could host similar environments. We sequenced environmental 16S rRNA genes and quantified microbial activity across a broad range of salinity and chaotropicity at a Mars-analogue salt harvesting facility in Southern California, where seawater is evaporated in a series of ponds ranging from kosmotropic NaCl brines to highly chaotropic MgCl 2 brines. Within NaCl brines, we observed a proliferation of specialized halophilic Euryarchaeota, which corresponded closely with the dominant taxa found in salterns around the world. These communities were characterized by very slow growth rates and high biomass accumulation. As salinity and chaotropicity increased, we found that the MgCl 2 -rich brines eventually exceeded the limits of microbial activity. We found evidence that exogenous genetic material is preserved in these chaotropic brines, producing an unexpected increase in diversity in the presumably sterile MgCl 2 -saturated brines. Because of their high potential for biomarker preservation, chaotropic brines could therefore serve as repositories of genetic biomarkers from nearby environments (both on Earth and beyond) making them prime targets for future life-detection missions.

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“…However, multimeric proteins are known to disintegrate upon changes in the environmental salt. Chaotropic anions at high concentrations, such as I – , Br – , and Cl – , promote the disassembly process and cause different levels of subunit dissociation, , although the size change was not as profound as temperature effect (Figure d). Also compared with the effect of high temperature, the gel did not proceed to degradation during the monitoring period, which is in accord with the reported conclusion that dissociation of the tetramer of hemoglobin induced by chaotropic salts steps to the dimer but not to the monomer in 1 M salt solution. , …”

Section: Resultsmentioning

confidence: 99%

Protein-Cross-Linked Hydrogels with Tailored Swelling and Bioactivity Performance: A Comparative Study

Ren

Wang

et al. 2016

ACS Appl. Mater. Interfaces

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The design of protein-based hydrogels that include biological activity independent of structural functionality is desirable for many bioengineering applications. Here a general route for construction of protein-based hydrogel is proposed by pretreatment of protein with thiolation agent and succeeding conjugation with 4-arm PEG-acrylate via Michael addition reaction. Different swelling behaviors responding to temperature and ions are comparatively studied for hydrogel cross-linked with hemoglobin (multimeric protein), albumin (monomeric protein), and dithiothreitol (DTT, small molecule). Meanwhile, the microscopic structure change is studied to correlate with the macroscopic hydrogel swelling behavior. Results show that proteins, which function as multisite cross-linkers, affect the gel swelling behaviors, and the effect is more profound for multimeric proteins when exposed to stimulus for protein dissociation. Moreover, the catalytic activity derived from hemoglobin is also preserved in the hydrogel, as demonstrated by the successfully synthesis of the colored product. By taking advantage of each particular protein, a broad range of functional materials can be expected for potential biomedical applications, such as stimuli-responsive hydrogel and immobilized enzyme.

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The Dissociation of Proteins by Chaotropic Salts

Cited by 97 publications

References 36 publications

Perchlorate enhances transmission in skeletal muscle excitation-contraction coupling.

Perchlorate enhances transmission in skeletal muscle excitation-contraction coupling.

Microbial diversity and activity in Southern California salterns and bitterns: analogues for remnant ocean worlds

Protein-Cross-Linked Hydrogels with Tailored Swelling and Bioactivity Performance: A Comparative Study

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