Kyushu University Academic Staff Educational and Research Activities Database
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Ozaki Shogo Last modified date:2018.07.31



Undergraduate School


Homepage
http://bunsei.phar.kyushu-u.ac.jp/BUNSEI-ENG.html
Phone
092-642-6643
Academic Degree
Ph.D
Country of degree conferring institution (Overseas)
No
Field of Specialization
Molecular biology, Microbiology, Genetics
Total Priod of education and research career in the foreign country
06years00months
Outline Activities
Initiation of chromosomal replication and its cell cycle-coordinated regulation bear crucial and fundamental mechanisms in most cellular organisms. Escherichia coli DnaA protein forms a homomultimeric complex with the replication origin (oriC). ATPDnaA multimers unwind the duplex within the oriC unwinding element (DUE). In this study, structural analyses suggested that several residues exposed in the central pore of the putative structure of DnaA multimers could be important for unwinding. Using mutation analyses, we found that, of these candidate residues, DnaA Val-211 and Arg-245 are prerequisites for initiation in vivo and in vitro. Whereas DnaA V211A and R245A proteins retained normal affinities for ATP/ADP andDNAand activity for the ATP-specific conformational change of the initiation complex in vitro, oriC complexes of these mutant proteins were inactive in DUE unwinding and in binding to the single-stranded DUE. Unlike oriC complexes including ADP-DnaA or the mutant DnaA, ATP-DnaA-oriC complexes specifically bound the upper strand of single- stranded DUE. Specific T-rich sequences within the strand were required for binding. The corresponding conserved residues of the DnaA ortholog in Thermotoga maritima, an ancient eubacterium, were also required for DUE unwinding, consistent
with the idea that the mechanism and regulation for DUE unwinding can be evolutionarily conserved. These findings provide novel insights into mechanisms for pore-mediated origin unwinding, ATP/ADP-dependent regulation, and helicase loading of the initiation complex.
Research
Research Interests
  • Mechanism and regulation for initiation complex that promotes local duplex DNA unwinding at replication origin during the initiation of chromosomal replication
    keyword : DNA replication, cell cycle, DnaA, AAA+, conformational change
    2005.10.
Academic Activities
Reports
1. Katayama, T, Ozaki, S, Keyamura, K, Fujimitsu, K., Regulation of the replication cycle: conserved and diverse regulatory systems for DnaA and oriC, Nat Rev Microbiol, 2010, 2010.03.
2. Ozaki S., Katayama T., DnaA structure, function, and dynamics in the initiation at the chromosomal origin., Plasmid, 2009.07.
Presentations
1. Shogo Ozaki, Lori Christian, Urs Jenal, The second messenger signaling drives chromosome replication in the asymmetrically dividing bacterium Caulobacter crescentus, 第56回日本生物物理学会年会, 2018.09.
2. Analysis on the minimal functional structure of the DnaA complex for the regulation of duplex DNA unwinding.
3. Analysis on the minimal functional elements of the replication origin in duplex DNA unwinding by DnaA.
Membership in Academic Society
  • American Society for Microbiology
  • The Japanese Biochemical Society
  • The Genetics Society of Japan
  • The Molecular Biology Society of Japan
Awards
  • Best Papers Awards in the 80th Annual Meeting of the Genetic Society of Japan
  • Best Papers Awards in the 79th Annual Meeting of the Genetic Society of Japan