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Proteomic discovery of cellular substrates of the ClpXP protease reveals five classes of ClpX-recognition signals.
These results represent a description of general rules governing substrate recognition by a AAA+ family ATPase and suggest strategies for regulation of protein degradation. Expand
Role of a Peptide Tagging System in Degradation of Proteins Synthesized from Damaged Messenger RNA
Variants of λ repressor and cytochrome b562 translated from messenger RNAs without stop codons were modified by carboxyl terminal addition of an ssrA-encoded peptide tag and subsequently degraded byExpand
The ClpXP and ClpAP proteases degrade proteins with carboxy-terminal peptide tails added by the SsrA-tagging system.
Having diverse degradation systems able to recognize this tag may increase degradation capacity, permit degradation of a wide variety of different tagged proteins, or allow SsrA-tagged proteins to be degraded under different growth conditions. Expand
AAA+ proteases: ATP-fueled machines of protein destruction.
The current understanding of the molecular mechanisms of substrate recognition, adaptor function, and ATP-fueled unfolding and translocation are reviewed. Expand
Transcription factors: structural families and principles of DNA recognition.
Familiarity, ease of access, trust, and awareness of benefits and risks to minimize uncertainty, will all be important for the sustained support of existing and new generations of DNA-B isolaters. Expand
OMP Peptide Signals Initiate the Envelope-Stress Response by Activating DegS Protease via Relief of Inhibition Mediated by Its PDZ Domain
It is shown that peptides ending with OMP-like C-terminal sequences bind the DegS PDZ domain, activate DegS cleavage of RseA, and induce sigma(E)-dependent transcription, suggesting that DegS acts as a sensor of envelope stress by binding unassembled OMPs. Expand
Sequence requirements for coiled-coils: analysis with lambda repressor-GCN4 leucine zipper fusions.
A genetic system developed in Escherichia coli to study leucine zippers with the amino-terminal domain of bacteriophage lambda repressor as a reporter for dimerization found many combinations of hydrophobic residues were found to be nonfunctional, and leucines in the heptad repeat were shown to have a special function inLeucine zipper diming. Expand
Structures of Asymmetric ClpX Hexamers Reveal Nucleotide-Dependent Motions in a AAA+ Protein-Unfolding Machine
These structures explain numerous solution studies of ClpX function, predict mechanisms for pore elasticity during translocation of irregular polypeptides, and suggest how repetitive conformational changes might be coupled to mechanical work during the ATPase cycle of Cl pX and related molecular machines. Expand
Rebuilt AAA + motors reveal operating principles for ATP-fuelled machines
It is shown that diverse geometric arrangements can support the enzymatic unfolding of protein substrates and translocation of the denatured polypeptide into the ClpP peptidase for degradation by covalently linking active and inactive subunits of the ATPase ClpX to form hexamers. Expand
Pore loops of the AAA+ ClpX machine grip substrates to drive translocation and unfolding
A tyrosine residue in a pore loop of the hexameric ClpX unfoldase links ATP hydrolysis to mechanical work by gripping substrates during unfolding and translocation, supporting a model in which nucleotide-dependent conformational changes in these pore loops drive substrate translocation and unfolding. Expand