The ATPase Activity of Chaperonin GroEL Is Highly Stimulated at Elevated Temperatures

1996 ◽  
Vol 229 (1) ◽  
pp. 271-274 ◽  
Author(s):  
Jose A. Mendoza ◽  
Terri Warren ◽  
Pam Dulin
Keyword(s):  
Atpase Activity ◽  
Elevated Temperatures ◽  
Chaperonin Groel

Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex

2010 ◽  
Vol 427 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Tomoya Sameshima ◽  
Ryo Iizuka ◽  
Taro Ueno ◽  
Takashi Funatsu
Keyword(s):  
Energy Transfer ◽  
Atpase Activity ◽  
Fluorescence Resonance Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Inhibitory Influence ◽  
Reaction Cycle ◽  
Chaperonin Groel ◽  
Denatured Proteins ◽  
Fluorescence Resonance

Controversy exists over whether the chaperonin GroEL forms a GroEL–(GroES)2 complex (football-shaped complex) during its reaction cycle. We have revealed previously the existence of the football-shaped complex in the chaperonin reaction cycle using a FRET (fluorescence resonance energy transfer) assay [Sameshima, Ueno, Iizuka, Ishii, Terada, Okabe and Funatsu (2008) J. Biol. Chem. 283, 23765–23773]. Although denatured proteins alter the ATPase activity of GroEL and the dynamics of the GroEL–GroES interaction, the effect of denatured proteins on the formation of the football-shaped complex has not been characterized. In the present study, a FRET assay was used to demonstrate that denatured proteins facilitate the formation of the football-shaped complex. The presence of denatured proteins was also found to increase the rate of association of GroES to the trans-ring of GroEL. Furthermore, denatured proteins decrease the inhibitory influence of ADP on ATP-induced association of GroES to the trans-ring of GroEL. From these findings we conclude that denatured proteins facilitate the dissociation of ADP from the trans-ring of GroEL and the concomitant association of ATP and the second GroES.

Parr–Smolt Transformation of Yearling Atlantic Salmon (Salmo salar) at Several Rearing Temperatures

1981 ◽  
Vol 38 (10) ◽  
pp. 1189-1198 ◽  
Author(s):  
C. E. Johnston ◽  
R. L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Salinity Tolerance ◽  
Elevated Temperatures ◽  
Salt Water ◽  
Effect Of Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
Thermal Effluent ◽  
Thermal Regimes

Six different rearing conditions were used to study the effect of temperature on seasonal changes in growth, condition factor, body silvering, body moisture and lipid content, salinity tolerance, and gill Na–K-ATPase activities of laboratory and pond-reared yearling Atlantic salmon (Salmo salar). Growth during the winter was greatest at the highest rearing temperature (16 °C) whereas those under simulated natural conditions grew slowest. Increasing temperatures in the spring stimulated growth more than constant temperature. Based on increased salinity tolerance, elevated ATPase activity, and growth in salt water, smolt development proceeded at all temperatures up to 16 °C. More smolts were produced in the high thermal regimes resulting in the best growth and the largest proportion of fish reaching smolt size. Unlike some Pacific salmonids, Atlantic salmon develop smolt status at temperatures as high as 16 °C. Yearling smolts can be produced at elevated temperatures and the use of thermal effluents for this purpose is promising.Key words: smoltification, smolt criteria, salinity tolerance, ATPase activity, rearing temperatures, elevated thermal regimes, thermal effluent, Salmo salar

Interaction of oxidized chaperonin GroEL with an unfolded protein at low temperatures

2012 ◽  
Vol 32 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Girish C. Melkani ◽  
Robin Sielaff ◽  
Gustavo Zardeneta ◽  
Jose A. Mendoza
Keyword(s):  
Atpase Activity ◽  
Low Temperatures ◽  
Hydrophobic Interactions ◽  
Hydrophobic Surfaces ◽  
Unfolded Protein ◽  
Native Proteins ◽  
Chaperonin Groel ◽  
Excess Amount ◽  
Substrate Proteins

The chaperonin GroEL binds to non-native substrate proteins via hydrophobic interactions, preventing their aggregation, which is minimized at low temperatures. In the present study, we investigated the refolding of urea-denatured rhodanese at low temperatures, in the presence of ox-GroEL (oxidized GroEL), which contains increased exposed hydrophobic surfaces and retains its ability to hydrolyse ATP. We found that ox-GroEL could efficiently bind the urea-unfolded rhodanese at 4°C, without requiring excess amount of chaperonin relative to normal GroEL (i.e. non-oxidized). The release/reactivation of rhodanese from GroEL was minimal at 4°C, but was found to be optimal between 22 and 37°C. It was found that the loss of the ATPase activity of ox-GroEL at 4°C prevented the release of rhodanese from the GroEL–rhodanese complex. Thus ox-GroEL has the potential to efficiently trap recombinant or non-native proteins at 4°C and release them at higher temperatures under appropriate conditions.

scholarly journals A novel cochaperonin that modulates the ATPase activity of cytoplasmic chaperonin.

1994 ◽  
Vol 125 (5) ◽  
pp. 989-996 ◽  
Author(s):  
Y Gao ◽  
R Melki ◽  
P D Walden ◽  
S A Lewis ◽  
C Ampe ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Beta Tubulin ◽  
Folding Process ◽  
Target Proteins ◽  
Chaperonin Groel ◽  
Significant Homology ◽  
Additional Protein ◽  
Cloned Cdna

The folding of alpha- and beta-tubulin requires three proteins: the heteromeric TCP-1-containing cytoplasmic chaperonin and two additional protein cofactors (A and B). We show that these cofactors participate in the folding process and do not merely trigger release, since in the presence of Mg-ATP alone, alpha- and beta-tubulin target proteins are discharged from cytoplasmic chaperonin in a nonnative form. Like the prokaryotic cochaperonin GroES, which interacts with the prototypical Escherichia coli chaperonin GroEL and regulates its ATPase activity, cofactor A modulates the ATPase activity of its cognate chaperonin. However, the sequence of cofactor A derived from a cloned cDNA defines a 13-kD polypeptide with no significant homology to other known proteins. Moreover, while GroES functions as a heptameric ring, cofactor A behaves as a dimer. Thus, cofactor A is a novel cochaperonin that is structurally unrelated to GroES.

Nested cooperativity in the ATPase activity of the oligomeric chaperonin GroEL

Biochemistry ◽  
1995 ◽  
Vol 34 (16) ◽  
pp. 5303-5308 ◽  
Author(s):  
Ofer Yifrach ◽  
Amnon Horovitz
Keyword(s):  
Atpase Activity ◽  
Chaperonin Groel

Surface water with more natural temperatures promotes physiological and endocrine changes in landlocked Atlantic salmon smolts

2021 ◽  
pp. 1-12 ◽  
Author(s):  
Amy M. Regish ◽  
William R. Ardren ◽  
Nicholas R. Staats ◽  
Henry Bouchard ◽  
Jonah L. Withers ◽  
...  
Keyword(s):  
Surface Water ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
Elevated Temperatures ◽  
Elevated Plasma ◽  
Return Rates ◽  
Hatchery Fish ◽  
Winter Temperatures ◽  
Water Fish ◽  
Natural Temperature

Hatchery salmonid smolts are often reared using groundwater with elevated temperatures to maximize growth. Previous work has shown that rearing hatchery smolts in surface water with a more natural thermal regime resulted in increased return rates of adult landlocked Atlantic salmon (Salmo salar). We evaluated whether landlocked Atlantic salmon reared in surface water with a natural temperature regime have altered physiological smolt characteristics compared with fish reared in groundwater with elevated winter temperatures. Hatchery fish were sampled three consecutive years from January to May. Additional fish were released as smolts, recaptured, and compared with fry-stocked smolts. Surface water smolts had earlier peaks of plasma T4, lower T3 levels, later peak cortisol, and lower gill Na+/K+-ATPase activity as compared with groundwater smolts. After release and recapture, surface water fish had elevated plasma T4 and gill Na+/K+-ATPase activity compared with groundwater fish, but less than stream-reared fish. Elevated plasma T4 in surface water fish in the hatchery and after release may have promoted imprinting and other aspects of smolt development, contributing to the higher adult return rates of a cohort reared in surface water.

Gastric H(+)-K(+)-ATPase activity is inhibited by reduction of disulfide bonds in beta-subunit

1992 ◽  
Vol 263 (1) ◽  
pp. C39-C46 ◽  
Author(s):  
D. C. Chow ◽  
C. M. Browning ◽  
J. G. Forte
Keyword(s):  
Atpase Activity ◽  
Disulfide Bonds ◽  
Elevated Temperatures ◽  
Sequence Data ◽  
Kinetic Studies ◽  
Monovalent Cation ◽  
Beta Subunit ◽  
Alpha Subunit ◽  
Cysteine Residues ◽  
High Concentrations

H(+)-K(+)-ATPase activity of rabbit isolated gastric microsomes was irreversibly inactivated by reducing agents, such as 2-mercaptoethanol and dithiothreitol. Similar to what has been observed for Na(+)-K(+)-ATPase, high concentrations of reagents, at moderately elevated temperatures, were required to inactivate H(+)-K(+)-ATPase, suggesting relative inaccessibility of the responsible disulfide bonds. Resistance against inactivation was conferred by monovalent cation activators of K(+)-stimulated ATPase and p-nitro-phenylphosphatase. The effectiveness of K+ congeners in protecting the enzyme was similar in sequence (Tl+ greater than K+ greater than Rb+) and concentration to their respective affinities for stimulating enzymatic activity, suggesting that the K(+)-bound form of the enzyme is more resistant to reduction than the free enzyme. Furthermore, Na+ antagonized the protective effect of K+. Labeling studies using fluorescein-maleimide indicated that 60-70% of the cysteine residues in the beta-subunit are in the oxidized form. Coupled with primary sequence data, this suggests that three disulfide bonds are present in the native beta-subunit. In contrast, less than 10% of the cysteine residues in the alpha-subunit are in the oxidized form. Kinetic studies showed that the 2-mercaptoethanol-induced loss of H(+)-K(+)-ATPase activity was correlated with a reduction of disulfide groups in the beta-subunit, while there was no significant change in the alpha-subunit. We conclude that reduction of disulfide bonds irreversibly inhibits H(+)-K(+)-ATPase activity, binding of K+ to the enzyme confers a resistance to disulfide bond reduction, and the responsible disulfide bonds are present in the beta-subunit.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

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