Details

Autor(en) / Beteiligte

• Konieczny, Igor
• Liberek, Krzysztof

Titel

Cooperative Action of Escherichia coli ClpB Protein and DnaK Chaperone in the Activation of a Replication Initiation Protein

Ist Teil von

• The Journal of biological chemistry, 2002-05, Vol.277 (21), p.18483-18488

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2002

Quelle

MEDLINE

Beschreibungen/Notizen

• The Escherichia coli molecular chaperone protein ClpB is a member of the highly conserved Hsp100/Clp protein family. Previous studies have shown that the ClpB protein is needed for bacterial thermotolerance. Purified ClpB protein has been shown to reactivate chemically and heat-denatured proteins. In this work we demonstrate that the combined action of ClpB and the DnaK, DnaJ, and GrpE chaperones leads to the activation of DNA replication of the broad-host-range plasmid RK2. In contrast, ClpB is not needed for the activation of the oriC-dependent replication of E. coli. Using purified protein components we show that the ClpB/DnaK/DnaJ/GrpE synergistic action activates the plasmid RK2 replication initiation protein TrfA by converting inactive dimers to an active monomer form. In contrast, Hsp78/Ssc1/Mdj1/Mge1, the corresponding protein system from yeast mitochondria, cannot activate the TrfA replication protein. Our results demonstrate for the first time that the ClpB/DnaK/DnaJ/GrpE system is involved in protein monomerization and in the activation of a DNA replication factor.