Structure-function studies of defense molecules found in horseshoe crab hemocytes

鲎血细胞中防御分子的结构功能研究

基本信息

批准号：
08458183
负责人：
KAWABATA Shun-ichiro
金额：
$ 5.38万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458183/
关键词：
Host defense Innate immunity Lipopolysaccharide Lectin リピドA

项目摘要

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.

我们确定了一种新型的马蹄蟹血细胞衍生的凝集素，我们将其命名为Tachylectin-4。与先前鉴定出的血细胞凝集素相比，它具有对人A-Tupe红细胞的有效性血凝活性，其与N-乙酰基葡萄糖胺（Tachylectin-2）具有亲和力。纯化的tachylectin-4是470 kDa的低聚糖蛋白，由30 kDa和31.5 kDa组成。 10mm时的Ca2+增强了血凝活性4倍，而活性则被EDTA和O-phenanthrotholine抑制。 100毫米处的L-羟基糖和N-乙酰神经氨酸酸完全抑制了tachylectin-4的活性。细菌S型脂多糖（LPS）也更强烈地抑制了活性，但不缺乏O-抗原的R型LPS。最有效的S-Type LPS是来自Escherichia Coil O111：B4，抑制对人A型红细胞的凝集所需的最低浓度（0.1mg/ml）比来自Salmonella Minnesota的S型LPS低160倍。因此，Colitose（3-脱氧-L-观糖）是大肠杆菌O111：B4中具有与L-观糖的结构相似性的独特糖，它是takelectin-4的特定配体的最可能的候选者。从血细胞cDNA文库中分离出tachylectin-4编码的cDNA。 1344碱基对的开放式阅读框架编码为成熟蛋白，用232个氨基酸编码。与任何其他已知的LPS结合凝集素都没有显着的序列相似性，而tchectin-4与NH2-末端结构域同源，具有Xenopus laevis pentraxin 1的功能。