PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9108300

Ligands regulate GroEL thermostability.

A K Surin·N V Kotova·I A Kashparov·V V Marchenkov·Marchenkova SYu·G V Semisotnov
View original source ↗Export metadata ↓

Abstract

Escherichia coli heat-shock proteins GroEL and GroES stimulate (in an ATP-dependent manner) the folding of various proteins. In this study scanning microcalorimetry was applied to investigate GroEL thermostability in the presence of its ligands. Mg2+ and K+ ions stabilize while ADP destabilizes the GroEL molecule against the action of temperature. Furthermore, ADP essentially increases the number of binding sites for the hydrophobic probe (ANS) and the number of GroEL SH-groups accessible to Ellman's reagent as well as the accessibility of the protein to the action of trypsin. The interaction of GroEL with GroES in the presence of Mg2+-ADP eliminates the destabilizing effect of ADP on the GroEL molecule against the action of temperature and Ellman's reagent but does not change its hydrophobicity and accessibility to trypsin.

Explore related subjects

Adenosine DiphosphateCalorimetry, Differential ScanningChaperonin 10Chaperonin 60Escherichia coliHot TemperatureLigandsProtein ConformationProtein DenaturationSolutionsThermodynamicsTrypsinJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A K Surin, N V Kotova, I A Kashparov, V V Marchenkov, Marchenkova SYu, G V Semisotnov. 1997-04-01. Ligands regulate GroEL thermostability.. https://doi.org/10.1016/s0014-5793(97)00199-3

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2022

A novel DPH5-related diphthamide-deficiency syndrome causing embryonic lethality or profound neurodevelopmental disorder.

PURPOSE: Diphthamide is a post-translationally modified histidine essential for messenger RNA translation and ribosomal protein synthesis. We present evidence for DPH5 as a novel cause of embryonic lethality and profound neurodevelopmental delays (NDDs). METHODS: Molecular testing was performed using exome or genome sequencing. A targeted Dph5 knockin mouse (C57BL/6Ncrl-Dph5em1Mbp/Mmucd) was created for a DPH5 p.His260Arg homozygous variant identified in 1 family. Adenosine diphosphate-ribosylation assays in DPH5-knockout human and yeast cells and in silico modeling were performed for the identified DPH5 potential pathogenic variants. RESULTS: DPH5 variants p.His260Arg (homozygous), p.Asn110Ser and p.Arg207Ter (heterozygous), and p.Asn174LysfsTer10 (homozygous) were identified in 3 unrelated families with distinct overlapping craniofacial features, profound NDDs, multisystem abnormalities, and miscarriages. Dph5 p.His260Arg homozygous knockin was embryonically lethal with only 1 subviable mouse exhibiting impaired growth, craniofacial dysmorphology, and multisystem dysfunction recapitulating the human phenotype. Adenosine diphosphate-ribosylation assays showed absent to decreased function in DPH5-knockout human and yeast cells. In silico modeling of the variants showed altered DPH5 structure and disruption of its interaction with eEF2. CONCLUSION: We provide strong clinical, biochemical, and functional evidence for DPH5 as a novel cause of embryonic lethality or profound NDDs with multisystem involvement and expand diphthamide-deficiency syndromes and ribosomopathies.

Adenosine Diphosphate↗
PubMed2001

Methyl pyruvate initiates membrane depolarization and insulin release by metabolic factors other than ATP.

The role of mitochondria in stimulus-secretion coupling of pancreatic beta-cells was examined using methyl pyruvate (MP). MP stimulated insulin secretion in the absence of glucose, with maximal effect at 5 mM. K+ (30 mM) alone, or in combination with diazoxide (100 microM), failed to enhance MP-induced secretion. Diazoxide (100 microM) inhibited MP-induced insulin secretion. MP depolarized the beta-cell in a concentration-dependent manner (5-20 mM). The sustained depolarization induced by 20 mM MP was not influenced by 100 microM diazoxide, but the continuous spiking activity was suppressed by 500 microM diazoxide. Pyruvate failed to initiate insulin release (5-20 mM) or to depolarize the membrane potential. ATP production in isolated beta-cell mitochondria was detected as accumulation of ATP in the medium during incubation in the presence of malate or glutamate in combination with pyruvate or MP. There was no difference in ATP production induced by pyruvate/malate or MP/malate in isolated beta-cell mitochondria. ATP production by MP/glutamate was higher than that induced by pyruvate/glutamate, but it was much lower than that induced by alpha-ketoisocaproate/glutamate. Pyruvate (5 mM) or MP (5 mM) had no effect on the ATP/ADP ratio in whole islets, whereas glucose (20 mM) significantly increased the whole islet ATP/ADP ratio. It is concluded that MP-induced beta-cell membrane depolarization or insulin release does not relate directly to mitochondrial ATP production. Instead MP may exert a direct extramitochondrial effect, or it may stimulate beta-cell mitochondria to produce coupling factors different from ATP to initiate insulin release.

Adenosine Diphosphate↗
PubMed2001

Adenosine diphosphate strongly potentiates the ability of the chemokines MDC, TARC, and SDF-1 to stimulate platelet function.

Platelet activation is normally induced by primary agonists such as adenosine diphosphate (ADP), thrombin, and collagen, whereas other agonists, such as epinephrine, can play important accessory roles. It is now reported that the macrophage-derived chemokine (MDC), thymus activation-regulated chemokine (TARC), and stromal cell-derived factor one (SDF-1) are highly effective activators of platelet function under a variety of conditions, stimulating platelet shape change, aggregation, and adhesion to collagen or fibrinogen. Chemokine-mediated platelet activation was rapid and maximal (less than 5 seconds) under arterial flow conditions and depended strongly on the presence of low levels of primary agonists such as ADP or thrombin. Concentrations of ADP (0.05-0.25 microM) or thrombin (0.005-0.02 U/mL) that induced minimal aggregation caused major aggregation acting in combination with the chemokines. The ability of apyrase to block chemokine-dependent aggregation or adhesion was consistent with an important role for ADP. Chemokine-stimulated aggregation was also insensitive to indomethacin, suggesting that the activation of cyclo-oxygenase is not involved. TARC, MDC, and SDF-1 increased intracellular calcium concentrations [Ca(2+)](i) when combined with low levels of ADP. The MDC and TARC receptor CCR4 was expressed on platelets, and an anti-CCR4 antibody blocked aggregation induced by TARC or MDC. Treatment of platelets with SDF-1 and MDC rapidly exposed P-selectin (CD62P) on the cell surface but did not induce the secretion of serotonin. These findings suggest that the chemokines MDC, TARC, and SDF-1, which may be produced during inflammatory responses, coupled with low levels of ADP or thrombin, can serve as strong stimuli for activating platelet function.

Adenosine Diphosphate↗