Integrated study on molecular evolution and biological functions of fish lectins

在系统发育树的基础上，对较长的鳗鱼凝集蛋白凝集蛋白I和凝集蛋白II的进化过程进行了研究，制备了凝集蛋白的可能祖先形式Con-ans。它们的热稳定性和糖特异性的比较表明，聚集蛋白是在显著的选择压力下通过加速进化来改善其功能的。从蔷薇中提取的多种c型凝集素BRA-1、bra -2和bra -3具有独特的糖结合特异性。凝集素对碳酸钙的结晶也有调节作用，表明它们参与了生物矿化。从多种鱼类的鱼卵中分离到多种l -鼠李糖结合凝集素（RBLs）并进行了鉴定；例如，钢头鳟鱼、鲑鱼、西班牙鲭鱼和阿尤鱼。rbl由同源亚基组成，具有约95个氨基酸残基的2-3个串联重复结构域。每个结构域都具有高度保守的8个半羧基，在同源位置有更多的ys残基和保守的肽基。rbl分别通过识别革兰氏阴性菌和革兰氏阳性菌表面的脂多糖和脂壁酸结构，特异性识别并结合globotriaosylceramide (Gb3)，并凝集革兰氏阴性菌和革兰氏阳性菌。它们还与一种微孢子虫寄生虫的孢子相互作用。来自鲑鱼卵的RBLs CSL1、2和3通过识别虹鳟鱼腹腔巨噬细胞（RTM5细胞）表面的Gb3诱导促炎细胞因子。此外，CSLs通过与Gb3结合对RTM5细胞有声光作用。CSLs诱导RTM5细胞产生活性氧呈剂量依赖性。该活性未被l -鼠李糖抑制，表明CSLs的糖结合位点不参与该活性。此外，一些rbl通过识别细胞上的Gb3诱导人结肠癌细胞凋亡。rbl的这些特性表明它们可能具有生物防御分子的功能。少

The evolutionary process of the conger eel galectins, congerin I and II, was investigated by preparing a probable ancestral form of congerins, Con-ans, on the basis of phylogenetic tree. The comparison among their thermostabilities and sugar specificities showed that congerins have evolved via accelerated evolution under significant selective pressure to improve their functions. The multiple C-type lectins, BRA-1, -2 and -3, from Megabalanus rosa, had characteristic and distinct sugar binding specificities. The lectins also had modulating effects on the crystallization of calcium carbonate, indicating their participation in biomineralization. Multiple L-rhamnose-binding lectins (RBLs) were isolated and characterized from the eggs of various fish species; i.e. steelhead trout, chum salmon, Spanish mackerel, and ayu. RBLs were composed of homologous subunits with 2-3 tandemly repeated domains of about 95 amino acid residues. Each domain could be characterized by highly conserved 8 half-C … More ys residues at homologous positions as well as the conserved peptide motifs. RBLs specifically recognized and bound to globotriaosylceramide (Gb3), and agglutinated Gram-negative and Gram-positive bacteria by recognizing the structures of lipopolysaccharides and lipoteichoic acid on their surfaces, respectively. They also interacted with the spores of a microsporidian parasite. RBLs from chum salmon eggs, CSL1, 2 and 3, induced proinflammatory cytokines by recognizing Gb3 on the surface of the peritoneal macrophage cell line (RTM5 cells) from rainbow trout. In addition, CSLs had an opsonic effect on RTM5 cells by binding to Gb3. CSLs induced the production of reactive oxygen species in dose-dependent manner in RTM5 cells. This activity was not inhibited by L-rhamnose, indicating that the sugar binding site of CSLs was not involved in the activity. Moreover, some RBLs induced apoptosis of human colon cancer cells by recognizing Gb3 on the cells. These properties of RBLs indicate that they may function as biodefence molecules. Less