15 Result(s)
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Article
An information theoretic framework reveals a tunable allosteric network in group II chaperonins
Identification of a tunable network of covarying residues within group II chaperonins suggests how these proteins support robust folding of their clients over a wide range of metabolic conditions.
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Article
Local slowdown of translation by nonoptimal codons promotes nascent-chain recognition by SRP in vivo
Analyses of yeast codon usage and ribosome profiling data reveal a nonoptimal codon cluster in the mRNAs of ER-targeted proteins, downstream of the SRP-binding site, that would slow down translation to promote...
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Article
Evolutionary conservation of codon optimality reveals hidden signatures of cotranslational folding
Rare or nonoptimal codons that cause ribosomes to pause have been suggested to be important determinants of cotranslational folding. A revised translational efficiency scale, which considers tRNA abundance as ...
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Article
The chaperonin TRiC blocks a huntingtin sequence element that promotes the conformational switch to aggregation
The eukaryotic group II chaperonin TRiC can block polyQ tract aggregation, present in proteins such as Htt. Here the TRiC-Htt interaction is examined using in vitro and in vivo experiments, revealing that TRiC do...
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Article
The Hsp90 mosaic: a picture emerges
Hsp90s, molecular chaperones critically involved in many essential cellular processes, were the focus of a recent international conference held in Seeon, Germany. The scope of the conference ranged from struct...
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Article
Defining the TRiC/CCT interactome links chaperonin function to stabilization of newly made proteins with complex topologies
The interactome of eukaryotic chaperonin TRiC/CCT is identified through a genome-wide approach, revealing an enrichment in large, multidomain proteins, or components of multimeric complexes, rich in hydrophobi...
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Article
Mechanism of lid closure in the eukaryotic chaperonin TRiC/CCT
Group II chaperonins, such as TriC/CCT, have a build-in lid that can cover the folding chamber and functions in an analogous way to the GroES-like proteins used by their Group I counterparts. Structural and mo...
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Article
Essential function of the built-in lid in the allosteric regulation of eukaryotic and archaeal chaperonins
Chaperonins are allosteric double-ring ATPases that mediate cellular protein folding. ATP binding and hydrolysis control opening and closing of the central chaperonin chamber, which transiently provides a prot...
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Protocol
Aberrant Protein Folding as the Molecular Basis of Cancer
Under normal growth conditions, tumor-suppressor proteins and oncogenes play key roles in the tight regulation of cell division (1). Tumorigenesis often arises from mutations that interfere with the appropriate f...
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Article
Where chaperones and nascent polypeptides meet
Two recent studies provide evidence for a direct interaction between the ribosomal protein L23 at the exit tunnel of the ribosome and the bacterial chaperone trigger factor, and between the eukaryotic L23 homo...
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Protocol
Purification of the Cytosolic ChaperoninTRiC from Bovine Testis
The chaperonins are oligomeric ring-complexes composed of ∼60 kDa sub- units, which mediate the folding of polypeptide chains in an ATP-dependent reaction (1). Class I chaperonins are found in prokaryotes and org...
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Protocol
Monitoring Actin Folding
Actin has been widely used as a model protein to study chaperone-mediated folding in vitro (1 2) and in vivo (3). In addition to being an essential and very abundant cytosolic protein, actin has the advantage of ...
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Protocol
Folding Assays
To determine the efficiency and rate of chaperone-mediated folding and renaturation, it is fundamental to have a good assay for the native conformation of the substrate protein. In the case of enzymes, the ide...
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Article
Co-translational domain folding as the structural basis for the rapid de novo folding of firefly luciferase
The 62 kDa protein firefly luciferase folds very rapidly upon translation on eukaryotic ribosomes. In contrast, the chaperone-mediated refolding of chemically denatured luciferase occurs with significantly slo...
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Article
Modulation of insulin induced ornithine decarboxylase by putrescine and methylputrescines in H-35 hepatoma cells
The effect of several methylputrescines on the activity of insulin-induced ornithine decarboxylase (ODC) was examined in H-35 hepatoma cells. The induction involved both protein and m-RNA synthesis. Actinomyci...
