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E. coli ClpA Catalyzed Polypeptide Translocation Is Allosterically Controlled by the Protease ClpP
- Source :
- Journal of Molecular Biology. 425:2795-2812
- Publication Year :
- 2013
- Publisher :
- Elsevier BV, 2013.
-
Abstract
- There are five known ATP-dependent proteases in Escherichia coli (Lon, ClpAP, ClpXP, HslUV, and the membrane-associated FtsH) that catalyze the removal of both misfolded and properly folded proteins in cellular protein quality control pathways. Hexameric ClpA rings associate with one or both faces of the cylindrically shaped tetradecameric ClpP protease. ClpA catalyzes unfolding and translocation of polypeptide substrates into the proteolytic core of ClpP for degradation through repeated cycles of ATP binding and hydrolysis at two nucleotide binding domains on each ClpA monomer. We previously reported a molecular mechanism for ClpA catalyzed polypeptide translocation in the absence of ClpP, including elementary rate constants, overall rate, and the kinetic step size. However, the potential allosteric effect of ClpP on the mechanism of ClpA catalyzed translocation remains unclear. Using single-turnover fluorescence stopped-flow methods, here we report that ClpA, when associated with ClpP, translocates polypeptide with an overall rate of ~35 aa s(-1) and, on average, traverses ~5 aa between two rate-limiting steps with reduced cooperativity between ATP binding sites in the hexameric ring. This is in direct contrast to our previously reported observation that, in the absence of ClpP, ClpA translocates polypeptide substrates with a maximum translocation rate of ~20 aa s(-1) with cooperativity between ATPase sites. Our results demonstrate that ClpP allosterically impacts the polypeptide translocation activity of ClpA by reducing the cooperativity between ATP binding sites.
- Subjects :
- Models, Molecular
medicine.medical_treatment
Endopeptidase Clp
ATPase
Allosteric regulation
Cooperativity
Biology
Models, Biological
Article
chemistry.chemical_compound
Adenosine Triphosphate
Allosteric Regulation
Structural Biology
Escherichia coli
medicine
ATP-Dependent Proteases
Binding site
Molecular Biology
Protein Unfolding
Protease
Escherichia coli Proteins
Kinetics
Protein Transport
Biochemistry
chemistry
biology.protein
Adenosine triphosphate
Subjects
Details
- ISSN :
- 00222836
- Volume :
- 425
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Biology
- Accession number :
- edsair.doi.dedup.....9550e88e62a172e05c8dd6fb1019ca85