1995 Fiscal Year Final Research Report Summary
Structure analysis of macrophage migration inhibitory factor
| Project/Area Number |
06454659
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Biophysics
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| Research Institution | Hokkaido University |
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Principal Investigator |
TANAKA Isao Hokkaido University, Graduate school of science, Professor, 大学院理学研究科, 教授 (70093052)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIHIRA Jun Hokkaido University, Faculty of Medicine, Lecturer, 医学部, 講師 (30189302)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Macrophage / Crystal / X-ray / Structure / Isomerization / Enzyme / MAD / Se-Met |
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| Research Abstract |
The macrophage migration inhibitory factor (MIF) is the first lymphokine discovered. It was originally identified by its ability to prevent the migration of guinea pig macrophages out of a capillary tube. Recent reports show that the role of MIF extends beyond the one it plays in the immune system. In this research project, the tertiary structure of the MIF from rat liver as well as human lymphocytes were determined by X-ray crystallography. Both proteins crystallized into two different crystal forms, each of which diffracts more than 2* resolution limit. The structure of rat MIF was determined by applying the multiwavelength anomalous diffraction (MAD) method. For the analysis, a series of Se-Met proteins were prepared by site-directed mutagenesis. This is the first example to apply protein engineering for preparing the"heavy atom derivatives"in an attempt to control the number and the sites of the"heavy atom"in the protein crystal. In contrast to the previous report, the MIF exists as a trimer in the crystal. The topology of the MIF protein fold and the architecture of the trimer is unique. However, MIF does share acommon general architecture with 5-carboxymethyl-2-hydroxymuconate isomerase from E.coli (CHMI) , in spite of the fact that there is no homology in the amino acid sequence in the two proteins. No one has ever expected the relationship between MIF and the isomerase. Thus, the X-ray structure analysis of MIF provides a new direction for the study of MIF.A number of interesting projects have been remained to be syudied in the future. They are the structure analysis of DOPD,the identification of real MIF substrate, the study of enzymatic mechanisms of MIF and the study of MIF receptor.
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