2001 Fiscal Year Final Research Report Summary
Development of antibiotics by monitoring the inhibition of the ATP-binding to DnaA, the initiator protein of chromosomal DNA replication in bacteria
| Project/Area Number |
12557210
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Biological pharmacy
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SEKIMIZU Kazuhisa The University of Tokyo, Graduate School of Pharmaceutical Sciences, Developmental Biochemistry, Professor, 大学院・薬学系研究科, 教授 (90126095)
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| Project Period (FY) |
2000 – 2001
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| Keywords | DnaA protein / Staphylococcus aureus / ATP-binding / basic phospholipid / acidic phospholipid / DNA replication / DNA polymerase III / silkworm |
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| Research Abstract |
Staphylococcus aureus causes opportunistic diseases for humans. In this study, we examined biochemical nature of Staphylococcus aureus DnaA protein, the replication initiator. Previous studies with Escherichia coli DnaA protein demonstrated that the ATP-binding form of DnaA protein is active, whereas the ADP-binding form is inactive. Purified Staphylococcus aureus DnaA proteins also showed high affinity for ATP and ADP. We showed that phosphatidylglycerol, an acidic phospholipids, stimulated the release of ADP from the ADP-DnaA complex, resulting in the activation of DnaA protein. Lysylphosphatidylglycerol, a basic phospholipid, was shown to inhibit the action of phosphatidylglycerol. Thus, phosphatidylglycerol may negatively regulate re-activation of DnaA protein. We propose here a new model of the regulation of initiation of DNA replication by increase in the content of basic phospholipids in cytoplasmic membranes.
We isolated mutants of Staphylococcus aureus whose DNA replication were temperature-sensitive. By complementation analysis, we identified polC, dnaE, and dnaC genes which are essential for DNA replication in the bacteria. We also established an animal model of infectious diseases by using silkworms. The system will provide a useful screening system for medicines against infectious diseases.
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