| Project/Area Number |
06672139
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical pharmacy
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| Research Institution | Japan Advanced Institute of Science and Technology |
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Principal Investigator |
TAKAHASHI Tetsuo Japan Advanced Institute of Science and Technology, Hokuriku, School of Materials Sci., Associate Professor, 材料科学研究科, 助教授 (90133769)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Phototaxis / Rhodopsin / Retinal / Chlamydomonas / Halobacteria / Archaebacteria / Behavior / Chemotaxis / Ectothiorhodospra halophila / Halobacterium halobium / Halobacterium salinarium / ISH / sensory vhodopsin / phoborhodopsin / H.halobium / phototaxis / photomorement / photophobic response / 光生物学 |
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| Research Abstract |
The absorption spectrum of phoborhodopsin (PR) of Halobacterium salinarium (H.salinarium) exhibits unique features : (1) The absorption maximum is nearly 100-nm blue shifted from those of other bacterial rhodopsins. (2) It shows vibrational fine structure at ambient temperatures. Our recent results are : .
1.13-demethyl retinal analog reconstitutes inverted photophobic responses in PR,while this analog confers no photochemical (of course no photobehavioral) activity to SR-I.
2. Conformation at C6-C7 bond of the chromophore has been confirmed to be s-trans in PR,whereas the chromophore binding site in PR is not so restricted like other archaebacterial rhodopsins. This has been the conclusion of an analog-reconstitution study using the both trans and cis retinal analogs in which C6-C7 conformation was locked with either a 5-membered or a 7-membered ring. Interestingly, PR analog pigment has been reconstituted from 6-s-cis locked (with 7-membered ring) retinal, which has a C5=C6-C7=C8 structure close to the native retinal at the chromophore binding site of visual rhodopsin. However, this PR analog showed no vibrational fine structure.
3. The primary sequence of PR in H.salinarium has been obtained quite recently, showing close homology to the related pigments of Natronobacterium pharaonis and Haloarcula vallismortis as well as bacteriorhodopsin (see also Zhang et al.Proc.Natl.Acad.Sci.93,8230-8235,1996) This and the above results confirmed that PR is a genuine member of the family of archaebacterial rhodopsins, leaving the unsolved problem of possible phylogenic relationship between archaebacterial rhodopsins and animal visual pigments.
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