2004 Fiscal Year Final Research Report Summary
Vectorial Photo-Energy Transmission on Chromophore-Array Constructed by DNA Assembly
| Project/Area Number |
13132207
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Kansai University |
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Principal Investigator |
OHYA Yuichi Kansai University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10213886)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANA Kazushige University of Hyogo, Faculty of Engineering, Professor, 大学院・工学研究科, 教授 (70192408)
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| Project Period (FY) |
2001 – 2004
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| Keywords | DNA / Energy transfer / Molecular assembly / Artificial photo-synthetic system / Self-organization / Femto-second laser / Photo-harvesting antenna / Complementary hydrogen bond |
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| Research Abstract |
Specific sequential arrangements of three kinds of chromophores separated by regulated distances equaling approximately one pitch of the DNA duplex (34 Å) in non-covalent molecular assembly systems are constructed using chromophore/oligo-DNA conjugates. Three different chromophores, 6-carboxy-4,5'-dichloro-2,7'-dimethoxyfluoresein (JOE), 6-carbxy-teramethylrhodamine (TAMRA), and 6-carboxy-X-rhodamine (ROX), were employed as the energy donor, mediator, and acceptor, respectively, based on their overlapping excitation and emission spectra. These chromophores were attached to the 5'-termials of 10mer oligo-DNAs with different sequences. The conjugates were mixed with matrix oligo-DNA (30mer) consisting of complementary sequences for the conjugates in order to construct a sequential JOE-TAMRA-ROX array (chromophore array) in a DNA duplex with 10 residues separating each chromophore component. Vectorial photoenergy transmission along the DNA helix axis by fluorescence resonance energy transfer (FRET) in a sequential chromophore array was observed and analyzed by time-resolved fluorescence spectroscopy and lifetime measurements using a femtosecond pulse laser system. The results suggest a FRET occurs on a picosecond scale between the donor chromophore and the acceptor chromophore through a mediator chromophore via a multi-step FRET over the molecular assemblies (two helical pitches, 68 Å). In addition, by introduction of donor chromophore (Fluorescein, Flu) at certain position of DNA duplex (20mer) and acceptor chromophore (hexachrolofluorescein, Hex) at terminal of 'DNA duplex, distance dependence of FRET between the chromophores was investigated. Moreover, by introduction of 2-5 donor chromophore (Flu) at certain position of DNA duplex and acceptor chromophore (Hex) at terminal of DNA duplex, photo-harvesting effects resulted from energy migration was also investigated. Photo-harvesting effect was observed.
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