ClpX protein of Escherichia coli activates bacteriophage Mu transposase in the strand transfer complex for initiation of Mu DNA synthesis

During transposition bacteriophage Mu transposase (MuA) catalyzes the transfer of a DNA strand at each Mu end to target DNA and then remains tightly bound to the Mu ends. Initiation of Mu DNA replication on the resulting strand transfer complex (STC1) requires specific host replication proteins and...

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Bibliographic Details
Published in:The EMBO journal 1996-02, Vol.15 (4), p.935-944
Main Authors: Kruklitis, R., Welty, D. J., Nakai, H.
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - physiology
ATPases Associated with Diverse Cellular Activities
Bacteriophage mu - genetics
Carrier Proteins - metabolism
DNA Nucleotidyltransferases - metabolism
DNA Replication
DNA, Viral - biosynthesis
Endopeptidase Clp
Escherichia coli
Escherichia coli - genetics
Escherichia coli Proteins
Gene Expression Regulation, Bacterial
Gene Expression Regulation, Viral
Integration Host Factors
Macromolecular Substances
Molecular Chaperones - metabolism
phage Mu
Transposases
Virus Replication
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Summary:During transposition bacteriophage Mu transposase (MuA) catalyzes the transfer of a DNA strand at each Mu end to target DNA and then remains tightly bound to the Mu ends. Initiation of Mu DNA replication on the resulting strand transfer complex (STC1) requires specific host replication proteins and host factors from two partially purified enzyme fractions designated Mu replication factors alpha and beta (MRFalpha and beta). Escherichia coli ClpX protein, a molecular chaperone, is a component required for MRFalpha activity, which removes MuA from DNA for the establishment of a Mu replication fork. ClpX protein alters the conformation of DNA‐bound MuA and converts STC1 to a less stable form (STC2). One or more additional components of MRFalpha (MRFalpha2) displace MuA from STC2 to form a nucleoprotein complex (STC3), that requires the specific replication proteins and MRFbeta for Mu DNA synthesis. MuA present in STC2 is essential for its conversion to STC3. If MuA is removed from STC2, Mu DNA synthesis no longer requires MRFalpha2, MRFbeta and the specific replication proteins. These results indicate that ClpX protein activates MuA in STC1 so that it can recruit crucial host factors needed to initiate Mu DNA synthesis by specific replication enzymes.
ISSN:0261-4189
1460-2075
DOI:10.1002/j.1460-2075.1996.tb00428.x