| Project/Area Number |
03041040
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Institution | Nagoya University |
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Principal Investigator |
MUKOHATA Yasuo Department of Biology, School of Science, Nagoya University Professor, 理学部, 教授 (10028110)
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| Co-Investigator(Kenkyū-buntansha) |
SUGIYAMA Yasuo Department of Biology, School of Science, Nagoya University. Research Associate, 理学部, 助手 (70154507)
KONISHI Tetsuya Department of Radiochemistry-biology, Niigata College of Pharmacy. Associate Pro, 薬学部, 助教授 (70057347)
KAMO Naoki Department of Biophysical chemistry, Faculty of Pharmaceutical Sciences, Hokkaid, 薬学部, 教授 (10001976)
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| Project Period (FY) |
1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1991: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | Halobacteria / Retinal protein / Light-driven H^+ pump / Bacteriorhodopsin / Archaerhodopsin / Light-driven C1^- pump / Halorhodopsin |
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| Research Abstract |
An extremely halophilic archaebacterium contains retinal proteins of 27 kDa single polypeptide. Bacteriorhodopsin (bR) and halorhodopsin (hR), both light-driven ion pumps, and sensory rhodopsin and phoborhodopsin, both photo-receptors, were found in Halobacterium halobium from North America. Archaerhodopsins (aR) were found in Halobacterium spp. from Western Australia. Pharaonis halorhodopsin (phR) was found in Natronobacterium pharaonis from North Africa. The amino acid sequence homologies were about 60% between H^+ pumps (bR and aRs) and between Cl^- pumps (hR and phR). Those were about 30% between H^+ and Cl^- pumps. The amino acid residues known to be important in the structure and function of bR are almost conserved in all retinal proteins. These suggest that halobacteria collected from different continents would have different ion pumps one another. In this project we surveyed the salt flats and salt pans in Argentina to collect such new halobacteria.
We collected 86 samples at Sa
… More
linas Grandes (salt flat near Salta city), and Salinas Grandes and Salinas Chica (salt pan in Peninsula Valdes) in January 1992. Aliquots of each samples were added to 5 ml culture for halobacteria and incubated at 40ﾟC. After a week, a culture was streaked on a agar plate and incubated at 40ﾟC. Stable strains with a different phenotype (white, faint orange, orange, red and reddish purple colored) were obtained. Cell envelope vesicles were prepared and assayed for light-induced ion pumping. At present several promising strains, which have both bR-like and hR-like proteins, were isolated. A halophilic metanogen was also isolated.
We are now ready to examine the photo-physiological nature of the pigmented strains and isolate retinal proteins from them. The photochemical properties and the amino acid sequences of those retinal proteins, which will be deduced from the DNA sequence of the gene for the corresponding protein, will be very much informative to the basic structure and mechanism of the light-driven ion pumps. Furthermore the evolutionary aspects of the retinal proteins would be rejuvenated. Less
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