| Project/Area Number |
08458183
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural biochemistry
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
KAWABATA Shun-ichiro Kyushu University・Faculty of Science, Associate Professor, 理学部, 助教授 (90183037)
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| Co-Investigator(Kenkyū-buntansha) |
MUTA Tatsushi Kyushu University・Faculty of Medicine, Assistant Professor, 医学部, 講師 (60222337)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥8,400,000 (Direct Cost: ¥8,400,000)
Fiscal Year 1997: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1996: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Host defense / Innate immunity / Lipopolysaccharide / Lectin / リピドA |
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| Research Abstract |
We identified a novel horseshoe crab hemocyte-derived lectin, which we named tachylectin-4. It has more potent hemagglutinating activity against human A-tupe erythrocytes than a previously identified hemocyte lectin with an affinity to N-acetylglucosamine, tachylectin-2. The purified tachylectin-4 is an oligomeric glycoprotein of 470 kDa, composed of subunits of 30 kDa and 31.5 kDa. Ca2+ at 10mM enhanced the hemagglutinatig activity 4-fold and the activity was inhibited by EDTA and o-phenanthroline. L-Fucose and N-acetylneuraminic acid at 100 mM completely inhibited the activity of tachylectin-4. The activity was also inhibited more strongly by bacterial S-type lipopolysaccharides (LPS) but not by R-type LPS lacking O-antigen. The most effective S-type LPS was from Escherichia coil O111 : B4 and the minimum concentration required for inhibiting agglutination against human A-type erythrocytes (0.1mg/ml) was 160-fold lower than those of S-type LPS from Salmonella minnesota. Therefore, colitose (3-deoxy-L-fucose), a unique sugar present in the O-antigen of Escherichia coli O111 : B4 with structural similarity to L-fucose, is the most probable candidate for a specific ligand of tachylectin-4. A cDNA coding for tachylectin-4 was isolated from a hemocyte cDNA library. The open reading frame of the 1344-base pair cDNA coded for the mature protein with 232 amino acids. There is no significant sequence similarity to any other known LPS-binding lectins, whereas tachylectin-4 is homologous to the NH2-terminal domain with unknown functions of Xenopus laevis pentraxin 1.
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