Abstract
ClpX binds substrates bearing specific classes of peptide signals, denatures these proteins, and translocates them through a central pore into ClpP for degradation. ClpX with the V154F po e mutation is severely defective in binding substrates bearing C-motif 1 degradation signals and is also impaired in a subsequent step of substrate engagement. In contrast, this mutant efficiently processes substrates with other classes of recognition signals both in vitro and in vivo. These results demonstrate that the ClpX pore functions in the recognition and catalytic engagement of specific substrates, and that ClpX recognizes different substrate classes in at least two distinct fashions.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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ATPases Associated with Diverse Cellular Activities
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / genetics*
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Adenosine Triphosphatases / metabolism*
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Amino Acid Sequence
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Binding Sites
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Catalysis
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Endopeptidase Clp
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Escherichia coli Proteins
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Kinetics
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Molecular Chaperones
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Molecular Sequence Data
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Mutagenesis
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Peptide Fragments / chemistry
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Protein Transport
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Recombinant Proteins / chemistry
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Recombinant Proteins / metabolism
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Restriction Mapping
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Substrate Specificity
Substances
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Escherichia coli Proteins
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Molecular Chaperones
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Peptide Fragments
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Recombinant Proteins
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Endopeptidase Clp
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Adenosine Triphosphatases
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ClpX protein, E coli
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ATPases Associated with Diverse Cellular Activities