| Project/Area Number |
09480170
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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 | 一般 |
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| Research Field |
Biophysics
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
TANAKA Isao Hokkaido Univ., Graduate School of Sciences, Pro., 大学院・理学研究科, 教授 (70093052)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIHIRA Jun Hokkaido Univ. Faculty of Medicals, Asso. Pro., 医学部, 助教授 (30189302)
NAKAGAWA Atsushi Osaka Univ., Institute for Protein Research, Asso. Pro., 蛋白質研究所, 助教授 (20188890)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1998: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1997: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | Crystal structure analysis of protein / DNA-binding proteins / Transcription factor |
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| Research Abstract |
In Escherichia coli, expression of the major outer membrane porin proteins. OmpC and OmpF, is regulated at the transcriptional level in response to medium osmolarity. Two regulatory factors, OmpR and EnvZ, are involved in this osmoregulation. OmpR is the cytoplasmic activator protein, which binds to the recognition sequence in both ompC and ompF promoters. The membrane-bound EnvZ senses the osmolarity outside the cell and exhibits OmpR-specific kinase and phosphatase activity. EnvZ-mediated phosphorylation of OmpR activates the protein, which results in binding to the omp genes. As is the case for many other response regulators, the 239 amino acid OmpR consists of two distinct domains: the N-terminal domain of OmpR contains a site that is phosphorylated and the C-terminal domain exhibits an inherent DNA-binding ability specific to the cognate promoters. An inspection of the E.coli genome DNA sequences revealed that there are at least 16 proteins whose amino acid sequences show extensive similarities to that of OmpR (OmpR-family of proteins). An amino acid sequence alignment with the tertiary structure of OmpR in hand suggests that all these family proteins are folded into a similar tertiary structure by the interactions of the well conserved hydrophobic residues. KdpE is one of the members of the OmpR-family, which is involved in the regulation of turgor pressure. One of the mutant proteins which show the ability to recognize KdpE promoter sites was purified and was successfully crystallized. The diffraction data was collected using synchrotron radiation at the Photon Factory.
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