| Co-Investigator(Kenkyū-buntansha) |
CUTTING Simo ロンドン大学, 講師
SCHUMANN Wol バイロイト大学, 教授
RUTMAN Andre ヘブライ大学, 助手
AMOS Oppenhe ヘブライ大学, 教授
BUKAU Bernd ハイデルベルグ大学, 助教授
JAFFE Aline パリ第7大学, ジャクモノ研究所, 助教授
YAMAZOE Mitsuyoshi Kumamoto University, School of Medicine, Instructor, 医学部, 助手 (00284745)
NIKI Hironori Kumamoto University, School of Medicine, Lecturer, 医学部, 講師 (70208122)
OGURA Teru Kumamoto University, School of Medicine, Associate Professor, 医学部, 助教授 (00158825)
SIMON Cutting University of London, Lecturer
WOLFGANG Schumann University of Bayreuth, Professor
ANDREW Joel Rutman The Hebrew University, Instructor
OPPENHEIM Amos B The Hebrew University, Professor
BERND Bukau University of Heidelberg, Associate Professor
ALINE Jaffe University Paris VII,Associate Professor
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| Research Abstract |
We have studied genes essential for chromosome partition, mukF,mukE,and mukB genes, in Escherichia coli. These muk genes constitute an operon. Tagged Muk proteins were purified to study their biochemical activities. Co-immunoprecipitaion experiments indicated that MukB,MukE,and MukF interact each other. Interaction between MukB and MukF was further confirmed by the analysis with the yeast two-hybrid system. We have developed a novel immunofluorescent microscopy to analyze protein distribution in the cell. Using the method, we have found that MukE proteins are localized as filaments, along the long axis, at one side of the cell periphery. EF-Tu, a cytoplasmic protein, TolC and Lpp, outer membrane proteins, were also showed to be localized as similar as MukE.These results indicate that a particular set of proteins forms together filaments. We named this structure "Membrtane-associated cytoskelton-like structure (MACS)". Structure of MACS is variable during cell cycle. We speculate that M
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ACS acts as rails on which MukB motor drives to carry chromosomal DNA.
We have also studied FtsH protease which degrades s32. A synthetic peptide corresponding to the C region of s32, which is essential for rapid degradation in vivo, was examined for in vitro degradation by FtsH,and it was found that the peptide was indeed cleaved by FtsH in an ATP-dependent fashion. We have introduced mutations in the Walker motif, the SRH region, and zinc-biding catalytic motif of FtsH by site-directed mutagenesis. The proteolytic activity of FtsH was greatly affected by these mutations. We have identified an suppressor mutation, sfhC,which allows DftsH cells to grow. Genetic analysis revealed that sfhC is allelic to fabZ whose product acts in phospholipid biosynthesis. In addition, ftsH mutations caused increase in the amount of lipopolysaccharide with overproduction of a key enzyme in lipopolysaccharide biosynthesis, EnvA,that resulted in formation of abnormal membrane structure in the periplasm. FtsH controls biosynthesis of these membrane components. We have also studied involvement of FtsH in sporulation in Bacillus subtilis. Less
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