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Molecular chaperones of the Hsp70 type transiently sequester unfolded segments of proteins and promote their correct folding. Target peptides were labeled with an environmentally sensitive fluorophore so that their binding to the molecular chaperone DnaK of Escherichia coli could be followed in real time. The two-step process was characterized by relaxation(More)
The molecular chaperone DnaK, the Hsp70 homolog of Escherichia coli, acts in concert with the co-chaperones DnaJ and GrpE. The aim of this study was to identify the particular phase of the peptide binding-release cycle of the DnaK/DnaJ/GrpE system that is directly responsible for the chaperone effects. By real-time kinetic measurements of changes in the(More)
Hsp70-Hsp40-NEF and possibly Hsp100 are the only known molecular chaperones that can use the energy of ATP to convert stably pre-aggregated polypeptides into natively refolded proteins. However, the kinetic parameters and ATP costs have remained elusive because refolding reactions have only been successful with a molar excess of chaperones over their(More)
Comparison of the amino acid sequences of nine different pyridoxal-5'-phosphate-dependent amino acid decarboxylases indicated that they can be subdivided into four different groups that seem to be evolutionarily unrelated to each other. Group I is represented by glycine decarboxylase, a component of a multienzyme system; group II comprises glutamate,(More)
A total of 150 amino acid sequences of vitamin B6-dependent enzymes are known to date, the largest contingent being furnished by the aminotransferases with 51 sequences of 14 different enzymes. All aminotransferase sequences were aligned by using algorithms for sequence comparison, hydropathy patterns and secondary structure predictions. The(More)
The assimilation of one-carbon (C1) compounds, such as methanol, by serine cycle methylotrophs requires the continuous regeneration of glyoxylate. Instead of the glyoxylate cycle, this process is achieved by a not yet established pathway where CoA thioesters are known to play a key role. We applied state-of-the-art metabolomics and (13)C metabolomics(More)
Biochemical and pharmacological effects of gamma-vinyl GABA (Vigabatrin, GVG), and irreversible enzyme-activated inhibitor of 4-aminobutyrate: 2-oxoglutarate aminotransferase (EC; GABA-T), were measured in mice. This anticonvulsant produced a time- and dose-dependent elevation of the GABA, phenylalanine and lysine contents of cortical tissue and(More)
A data base was compiled containing the amino acid sequences of 12 aspartate aminotransferases and 11 other aminotransferases. A comparison of these sequences by a standard alignment method confirmed the previously reported homology of all aspartate aminotransferases and Escherichia coli tyrosine aminotransferase. However, no significant similarity between(More)
Several metals and metalloids profoundly affect biological systems, but their impact on the proteome and mechanisms of toxicity are not fully understood. Here, we demonstrate that arsenite causes protein aggregation in Saccharomyces cerevisiae. Various molecular chaperones were found to be associated with arsenite-induced aggregates indicating that this(More)
Aspartate aminotransferase is a pyridoxal phosphate-dependent enzyme that catalyses the transamination reaction: L-aspartate + 2-oxoglutarate----oxaloacetate + L-glutamate. The enzyme shuttles between its pyridoxal and pyridoxamine forms in a double-displacement process. This paper proposes a mechanism of action that delineates the dynamic role of the(More)