1988 Fiscal Year Final Research Report Summary
Time-resolved EXAFS method for analyses of dynamical structure of biopolymers
| Project/Area Number |
61880025
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
生物物性学
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| Research Institution | The Institute of Physicaland Chemical Research |
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Principal Investigator |
IIZUKA Tetsutaro The Institute of Physical and Chemical Research, 生体物理化学研究室, 主任研究員 (30029475)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRO Yoshitsugu The Institute of Physical and Chemical Research, 生体物理化学研究室, 研究員 (70183051)
高橋 勝緒 理化学研究所, 生体物理化学研究室, 副主任研究員 (30087580)
SHIMADA Hideo School of Medicine, Keio University, 医学部, 助手 (80095611)
MAKINO Ryu School of Medicine, Keio University, 医学部, 講師 (40101026)
TAKAHASHI Katsuo The Institute of Physical and Chemical Research
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| Project Period (FY) |
1986 – 1988
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| Keywords | Time-Resolved EXAFS / Laser-Photolysis / Myoglobin / Hemoglobin / XANES / Peroxidase / Cytochrome P450 / 動的構造解析 |
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| Research Abstract |
Recently X-ray absorption spectroscopy has been widely applied to metallo-proteins for the purpose of determining the local structure in the vicinity of metal ions. In contrast with X-ray crystallography, this mothod has a great advantage in its applicability to the structural analyses of either solution or amorphous samples. In the case of iron, the absorption spectrum originating from the excitation of K-electron in is orbital of iron is observed around 7.1 KeV and gives fine structures abbreveated as EXAFS(Extended X-ray Absorption Fine Structure) and XANES(X-ray Absorption Near Edge Structure). These fine structures reflect both environmental and electronic structures of iron such as distance between iron and nearest ligands, iron coordination numbers, species of the nearest ligands, bond angles, 1s-3d transition, and etc.
In this study we tried to develop a system for analyses of dynamic structures of metallo-proteins and -enzymes, by employing an X-ray fluorescence-detector constructed by Oyanagi et al. at the Photon Factory of Tsukuba.
(1) We devised optical monitor and laser-photolysis systems for detecting and exciting the electronic states of samples, both of which were conected to the X-ray fluorescence-detector above together with several interfaces and optical fibers.
(2) In order to test the whole system, typical and stable hemoproteins such as sperm whale myoglobin and porcine hemoglobin were employed. The CO complexes of these proteins have great advantages in testing the system due to the reversible properties in photo-induced dissociation and thermal reconbination of CO from and to heme-iron of the proteins.
(3) By using above system, we measured X-ray absorption spectra of various hemoproteins including myoglobin, hemoglobin, peroxidase and cytochrome P450.
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