A new component of bacteriophage Mu replicative transposition machinery: the Escherichia coli ClpX protein.
We have shown previously that some particular mutations in bacteriophage Mu repressor, the frameshift vir mutations, made the protein very sensitive to the Escherichia coli ATP-dependent Clp protease. This enzyme is formed by the association between a protease subunit (ClpP) and an ATPase subunit. ClpA, the best characterized of these ATPases, is not required for the degradation of the mutant Mu repressors. Recently, a new potential ClpP associated ATPase, ClpX, has been described. We show here that this new subunit is required for Mu vir repressor degradation. Moreover, ClpX (but not ClpP) was found to be required for normal Mu replication. Thus ClpX has activities that do not require its association with ClpP. In the pathway of Mu replicative transposition, the block resides beyond the strand transfer reaction, i.e. after the transposition reaction per se is completed, suggesting that ClpX is required for the transition to the formation of the active replication complex at one Mu end. This is a new clear-cut case of the versatile activity of polypeptides that form multi-component ATP-dependent proteases.
Unité Transposition Bactérienne, Université Libre de Bruxelles, Rhode St Genèse, Belgium.
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Mhammedi-Alaoui
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Pato
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MJ
Gama
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Toussaint
D049069:ATP-Dependent Proteases; D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D010583:Bacteriophage mu / Q000254:growth & development* / Q000472:pathogenicity; D004261:DNA Replication; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism; D008242:Lysogeny; D018832:Molecular Chaperones; D011995:Recombination, Genetic; D012097:Repressor Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins; D014774:Virulence; D014779:Virus Replication
D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D012097:Repressor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C088072:ClpX protein, E coli; D000074183:ATPases Associated with Diverse Cellular Activities