Dynamic assembly of Hda and the sliding clamp in the regulation of replication licensing.
Regulatory inactivation of DnaA (RIDA) is one of the major regulatory mechanisms of prokaryotic replication licensing. In RIDA, the Hda-sliding clamp complex loaded onto DNA directly interacts with adenosine triphosphate (ATP)-bound DnaA and stimulates the hydrolysis of ATP to inactivate DnaA. A prediction is that the activity of Hda is tightly controlled to ensure that replication initiation occurs only once per cell cycle. Here, we determined the crystal structure of the Hda-β clamp complex. This complex contains two pairs of Hda dimers sandwiched between two β clamp rings to form an octamer that is stabilized by three discrete interfaces. Two separate surfaces of Hda make contact with the β clamp, which is essential for Hda function in RIDA. The third interface between Hda monomers occludes the active site arginine finger, blocking its access to DnaA. Taken together, our structural and mutational analyses of the Hda-β clamp complex indicate that the interaction of the β clamp with Hda controls the ability of Hda to interact with DnaA. In the octameric Hda-β clamp complex, the inability of Hda to interact with DnaA is a novel mechanism that may regulate Hda function.
Department of Life Science, Pohang University of Science and Technology, 35398 Pohang, South Korea.
Jin S
JS
Kim
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14228, USA.
Michael T
MT
Nanfara
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Mi 48824-1319, USA.
Sundari
S
Chodavarapu
Pohang Accelerator Laboratory, Pohang University of Science and Technology, 35398 Pohang, South Korea.
Kyeong S
KS
Jin
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14228, USA.
Vignesh M P
VMP
Babu
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14228, USA.
Mohamed A
MA
Ghazy
Department of Life Science, Pohang University of Science and Technology, 35398 Pohang, South Korea.
Scisung
S
Chung
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Mi 48824-1319, USA.
Jon M
JM
Kaguni
Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14228, USA.
Mark D
MD
Sutton
Department of Life Science, Pohang University of Science and Technology, 35398 Pohang, South Korea.
Yunje
Y
Cho
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D004258:DNA Polymerase III / Q000737:chemistry* / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D055503:Protein Multimerization; D016415:Sequence Alignment
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; C101139:beta subunit, DNA polymerase III; D004258:DNA Polymerase III; D000251:Adenosine Triphosphatases; C435211:Hda protein, E coli