Frédérique Weber

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As a basic principle, assisted protein folding by GroEL has been proposed to involve the disruption of misfolded protein structures through ATP hydrolysis and interaction with the cofactor GroES. Here, we describe chaperonin subreactions that prompt a re-examination of this view. We find that GroEL-bound substrate polypeptide can induce GroES cycling on and(More)
Total transfer RNAs were extracted from highly purified potato mitochondria. From quantitative measurements, the in vivo tRNA concentration in mitochondria was estimated to be in the range of 60 microM. Total potato mitochondrial tRNAs were fractionated by two-dimensional polyacrylamide gel electrophoresis. Thirty one individual tRNAs, which could read all(More)
Two models are being considered for the mechanism of chaperonin-assisted protein folding in E. coli: (i) GroEL/GroES act primarily by enclosing substrate polypeptide in a folding cage in which aggregation is prevented during folding. (ii) GroEL mediates the repetitive unfolding of misfolded polypeptides, returning them onto a productive folding track. Both(More)
σ Receptor ligands are attracting interest as possible anti-cancer agents because of their ability to induce cell death by different mechanisms. In this study we investigated the cytotoxic effects of 12 recently developed σ-receptor ligands in a panel of eight different human tumor cell lines by either the crystal violet or MTT assays. The results show that(More)
The 8,8'-biquinoline-5,5'-diones 2A are formed by the erythroquine and thalleioquine reaction from the 6-methoxyquinolines 1 as model compounds. The red substances 2A react with hydrochloric acid to yield the yellow biquinolinedihydrochlorides 3. The structure of 3b dihydrate is determined by X-ray crystal analysis. The redox properties of 2A are(More)
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