Formation of the preprimosome protects lambda O from RNA transcription-dependent proteolysis by ClpP/ClpX.
Using the bacteriophage lambda DNA replication system, composed entirely of purified proteins, we have tested the accessibility of the short-lived lambda O protein to the ClpP/ClpX protease during the various stages of lambda DNA replication. We find that binding of lambda O protein to its orilambda DNA sequence, leading to the so-called "O-some" formation, largely inhibits its degradation. On the contrary, under conditions permissive for transcription, the lambda O protein bound to the orilambda sequence becomes largely accessible to ClpP/ClpX-mediated proteolysis. However, when the lambda O protein is part of the larger orilambda:O.P.DnaB preprimosomal complex, transcription does not significantly increase ClpP/ClpX-dependent lambda O degradation. These results show that transcription can stimulate proteolysis of a protein that is required for the initiation of DNA replication.
Zylicz
M
M
Department of Molecular and Cellular Biology, Faculty of Biotechnology, University of Gdansk, 80-822 Gdansk, Kladki 24, Poland. zylicz@biotech.univ.gda.pl
Liberek
K
K
Wawrzynow
A
A
Georgopoulos
C
C
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins; D010582:Bacteriophage lambda / Q000235:genetics* / Q000502:physiology; D004265:DNA Helicases / Q000378:metabolism; D004261:DNA Replication; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D053488:DnaB Helicases; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000821:virology; D007700:Kinetics; D008957:Models, Genetic; D018741:Replication Origin; D012697:Serine Endopeptidases / Q000378:metabolism*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
D001426:Bacterial Proteins; D004279:DNA, Viral; C027812:O protein, Bacteriophage lambda; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases; D012697:Serine Endopeptidases; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D053488:DnaB Helicases