Hung Le Dinh, Sato Yuichiro, Hori Kanji
Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi - Hiroshima 739-8528, Japan; Nhatrang Institute of Technology Research and Application, 2A-Hungvuong Street, Nhatrang City, Khanhhoa Province, Viet Nam.
Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi - Hiroshima 739-8528, Japan; Faculty of Pharmacy, Yasuda Women's University, 6-13-1 Yasuhigashi, Asaminami, Hiroshima 731-0153, Japan.
Phytochemistry. 2011 Jun;72(9):855-61. doi: 10.1016/j.phytochem.2011.03.009. Epub 2011 Apr 12.
From a fresh sample (1 kg) of cultivated red alga Kappaphycus striatum, three isolectins, KSA-1 (15.1 mg), KSA-2 (58.0 mg) and KSA-3 (6.9 mg), were isolated by a combination of extraction with aqueous ethanol, ethanol precipitation, and ion exchange chromatography. Isolated KSAs were monomeric proteins of about 28kDa having identical 20N-terminal amino acid sequences to each other. Their hemagglutination activities were not inhibited by monosaccharides, but inhibited by glycoproteins bearing high-mannose N-glycans. In a binding experiment with pyridylaminated oligosaccharides by centrifugal ultrafiltration-HPLC assay, the isolectin KSA-2 was exclusively bound to high-mannose type N-glycans, but not to other glycans. Including complex types and a pentasaccharide core of N-glycans, indicating that it recognized branched oligomannosides. The binding activity of KSA-2 was slightly different among high-mannose N-glycans examined, indicating that the lectin has a higher affinity for those having the exposed (α1-3) Man in the D2 arm. On the other hand, KSA-2 did not bind to a free oligomannose that is a constituent of the branched oligomannosides, implying that the portion of the core GlcNAc residue(s) of the N-glycans is also essential for binding. Thus, KSA-2 appears to recognize the extended carbohydrate structure with a minimal length of a tetrasaccharide, Man(α1-3)Man(α1-6)Man(β1-4)GlcNAc. This study indicates that K. striatum, which has extensively been cultivated as a source of carrageenan, is a good source of a valuable lectin(s) that is strictly specific for high-mannose N-glycans.
从新鲜的养殖红藻卡帕藻（1千克）样本中，通过乙醇水溶液萃取、乙醇沉淀和离子交换色谱相结合的方法，分离出三种异凝集素，即KSA - 1（15.1毫克）、KSA - 2（58.0毫克）和KSA - 3（6.9毫克）。分离得到的KSA是约28kDa的单体蛋白，它们彼此具有相同的20个N端氨基酸序列。它们的血凝活性不受单糖抑制，但受带有高甘露糖型N -聚糖的糖蛋白抑制。在通过离心超滤 - HPLC测定法与吡啶氨基化寡糖的结合实验中，异凝集素KSA - 2仅与高甘露糖型N -聚糖结合，而不与其他聚糖结合，包括N -聚糖的复杂类型和五糖核心，表明它识别分支寡甘露糖苷。在所检测的高甘露糖N -聚糖中，KSA - 2的结合活性略有不同，这表明该凝集素对在D2臂中具有暴露的（α1 - 3）甘露糖的那些聚糖具有更高的亲和力。另一方面，KSA - 2不与作为分支寡甘露糖苷组成部分的游离寡甘露糖结合，这意味着N -聚糖的核心GlcNAc残基部分对于结合也是必不可少的。因此，KSA - 2似乎识别具有至少四糖长度的延伸碳水化合物结构，即Man(α1 - 3)Man(α1 - 6)Man(β1 - 4)GlcNAc。这项研究表明，作为卡拉胶来源而被广泛养殖的卡帕藻是一种宝贵凝集素的良好来源，该凝集素对高甘露糖N -聚糖具有严格的特异性。
