The N terminus of ClpB from Thermus thermophilus is not essential for the chaperone activity
| Autor: | Philipp Beinker, Jochen Reinstein, Sandra Schlee, Yvonne Groemping, Ralf Seidel |
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| Rok vydání: | 2002 |
| Předmět: |
Time Factors
Protein family Allosteric regulation Plasma protein binding Biochemistry Protein Structure Secondary Substrate Specificity Adenosine Triphosphate Polylysine Binding site Luciferases Molecular Biology Heat-Shock Proteins Adenosine Triphosphatases Binding Sites biology Dose-Response Relationship Drug Circular Dichroism Escherichia coli Proteins Hydrolysis Thermus thermophilus Cell Biology Endopeptidase Clp biology.organism_classification Protein Structure Tertiary Kinetics Spectrometry Fluorescence Cyclic nucleotide-binding domain Chaperone (protein) biology.protein Chromatography Gel CLPB Plasmids Protein Binding |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 0021-9258 |
| Popis: | ClpB from Thermus thermophilus belongs to the Clp/Hsp100 protein family and reactivates protein aggregates in cooperation with the DnaK chaperone system. The mechanism of protein reactivation and interaction with the DnaK system remains unclear. ClpB possesses two nucleotide binding domains, which are essential for function and show a complex allosteric behavior. The role of the N-terminal domain that precedes the first nucleotide binding domain is largely unknown. We purified and characterized an N-terminal shortened ClpB variant (ClpBDeltaN; amino acids 140-854), which remained active in refolding assays with three different substrate proteins. In addition the N-terminal truncation did not significantly change the nucleotide binding affinities, the nucleotide-dependent oligomerization, and the allosteric behavior of the protein. In contrast casein binding and stimulation of the ATPase activity by kappa-casein were affected. These results suggest that the N-terminal domain is not essential for the chaperone function, does not influence the binding of nucleotides, and is not involved in the formation of intermolecular contacts. It contributes to the casein binding site of ClpB, but other substrate proteins do not necessarily interact with the N terminus. This indicates a substantial difference in the binding mode of kappa-casein that is often used as model substrate for ClpB and other possibly more suitable substrate proteins. |
| Databáze: | OpenAIRE |
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