Escherichia coli ClpB is a non-processive polypeptide translocase
| Autor: | Aaron L. Lucius, JiaBei Lin, Clarissa L. Weaver, Tao Li, Elizabeth C. Duran, Justin M. Miller |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
AAA+ motor proteins
medicine.medical_treatment Proteolysis Molecular Sequence Data Biology medicine.disease_cause Biochemistry Protein Structure Secondary 03 medical and health sciences 0302 clinical medicine medicine Translocase chaperones protein disaggregation Amino Acid Sequence Molecular Biology Escherichia coli Peptide sequence Research Articles Heat-Shock Proteins 030304 developmental biology pre-steady-state kinetics 0303 health sciences Protease medicine.diagnostic_test Escherichia coli Proteins Cell Biology Protein engineering Förster resonance energy transfer (FRET) Endopeptidase Clp 3. Good health Förster resonance energy transfer Bacterial Translocation biology.protein CLPB Peptides 030217 neurology & neurosurgery Research Article |
| Zdroj: | Biochemical Journal |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | Here we show that ClpB is a non-processive translocase that takes, at most, two steps on the polypeptide backbone before dissociation. These findings indicate that ClpB is not likely to translocate polypeptide through its axial channel as previously concluded. Escherichia coli caseinolytic protease (Clp)B is a hexameric AAA+ [expanded superfamily of AAA (ATPase associated with various cellular activities)] enzyme that has the unique ability to catalyse protein disaggregation. Such enzymes are essential for proteome maintenance. Based on structural comparisons to homologous enzymes involved in ATP-dependent proteolysis and clever protein engineering strategies, it has been reported that ClpB translocates polypeptide through its axial channel. Using single-turnover fluorescence and anisotropy experiments we show that ClpB is a non-processive polypeptide translocase that catalyses disaggregation by taking one or two translocation steps followed by rapid dissociation. Using single-turnover FRET experiments we show that ClpB containing the IGL loop from ClpA does not translocate substrate through its axial channel and into ClpP for proteolytic degradation. Rather, ClpB containing the IGL loop dysregulates ClpP leading to non-specific proteolysis reminiscent of ADEP (acyldepsipeptide) dysregulation. Our results support a molecular mechanism where ClpB catalyses protein disaggregation by tugging and releasing exposed tails or loops. |
| Databáze: | OpenAIRE |
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