1992 Fiscal Year Final Research Report Summary
Molecular assembly of Limulus polyphemus hemocyanin by using small angle X-ray scattering
| Project/Area Number |
03680232
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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 |
生物物性学
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| Research Institution | DOKKYO UNIVERSITY SCHOOL OF MEDICINE |
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Principal Investigator |
IGARASHI Yoshihiko DOKKYO UIV.SCH.MED. BIOCHEMISTRY ASSISTANT PROFESSOR, 医学部, 助教授 (50049235)
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| Co-Investigator(Kenkyū-buntansha) |
ICHIMURA Kaoru DOKKYO UIV.SCH.MED. BIOCHEMISTRY ASSISTANT, 医学部, 助手 (40213011)
KIMURA Kazumoto DOKKYO UIV.SCH.MED.MED. ELECTRONICS RESERCHER, 医学部, 研究員 (30049241)
KIHARA Hiroshi JICHI MED.SCH.SCH.NURSING PHYSICS PROFESSOR, 物理・教庭, 教授 (20049076)
KAJITA Akihiko DOKKYO UIV.SCH.MED. BIOCHEMISTRY HONORABLE PROFESSOR, 医学部, 名誉教授 (80049113)
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| Project Period (FY) |
1991 – 1992
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| Keywords | HEMOCYANIN / PANULIRUS JAPONICUS / PROCAMBARUS CLARKI / MACROCHEIRA KAEMPFERI / LIMULUS POLYPHEMUS / SUBUNIT ASSEMBLY / SUBMULTIPLE / SMALL ANGLE X-RAY SCATTERING |
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| Research Abstract |
Structures in a solution of giant molecules which can not been analyzed by X-ray crystallography were evaluated successfully by using small angle X-ray scattering (SAXS). In 1991, we analyzed the hexameric structure of Panulirus japonicus hemocyanin and compared its scattering pattern with 1) - 3) models.
type 1 : a large sphere model : hexamers (submultiples) are regarded as one sphere.
type 2 : a small sphere model : subunits are regarded as one sphere. The submultiple consists of 6 spheres. The configuration of each subunit was followed by X-ray crystallography.
type 3 : an atomic coordinates model : alpha carbon coordinates are the center of small beads as shown in P. interuputus Hc by X-ray crystallographic analysis. The configuration of each subunit was the same as type 2 model.
The results show that the scattering pattern of type 3 model fits the experimental data better than other two models. Thus, the structure in the solution of the P. japonicus Hc was shown to be quite similar to that of Hc in crystal. In 1992, we applied SAXS to 12-mer Hc which has never been evaluated by X-ray crystallography because this Hc is too large to be analyzed by this method. We used three 12-mer Hcs ; Limulus polyphemus (class : Merostomata), Procambarus clarki and Macrocheira Kaempferi (class : Crustacea). On the assumption that the submultiple structure of those Hc was the same as that of P. interuputus, we calculated the scattering patterns of assembly of submultiples using following models.
type a : One submultiple is put on the other. (Two submultiples coincided with 3-fold axis.)
type b : One side of submultiple is contacted with each other.
In conclusion, the structure of Merostomata 12-mer Hc was of type b model and that of Crustacea Hcs of type a model. We demonstrated clearly there was a large difference in the assembly manner of submultiples between the two classes of arthropodan Hc.
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