Department of Zoology, Holy Cross College (Autonomous), Nagercoil, India; Affiliated to Manonmaniam Sundaranar University, Tirunelveli, 627 012, Tamil Nadu, India.
Department of Zoology, Holy Cross College (Autonomous), Nagercoil, India; Affiliated to Manonmaniam Sundaranar University, Tirunelveli, 627 012, Tamil Nadu, India.
Protein Expr Purif. 2024 Oct;222:106536. doi: 10.1016/j.pep.2024.106536. Epub 2024 Jun 21.
Lectins are versatile proteins that specifically recognize and interact with sugar moieties expressed on the cell surface. The potential of lectin in drug targeting and delivery has instigated interest to identify natural lectins. Crabs have been identified as a rich source of lectin because the innate immune system is activated on encounter of pathogens and helps in the production of lectin. Although the presence of lectins in crab's hemolymph is well documented, little information about lectin in hepatopancreas, a vital organ for immunity and digestion in crustaceans, is currently available. A calcium dependent lectin (75 kDa) was purified from the hepatopancreas of the freshwater crab Oziotelphusa naga by bioadsorption and fetuin linked Sepharose 4B affinity chromatography technique. The isolated hepatopancreas lectin is calcium dependent and maximum agglutination was observed with rabbit erythrocytes. The hemagglutinating activity of the hepatopancreas lectin was effectively inhibited by sugars, such as α-lactose, GlcNAc, trehalose and NeuAc. Compared to sialylated N-glycosylated proteins including transferrin and apo transferrin, sialylated O-glycosylated proteins like fetuin exhibited stronger inhibitory effect. The ability of erythrocytes to bind hepatopancreas lectin has been diminished by desialylation of the potent inhibitor, indicating the significance of sialic acid in lectin-ligand interactions. The purified hepatopancreas lectin showed a broad spectrum of antimicrobial activity against bacteria Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, E. coli and fungi Candida albicans and Aspergillus niger. The findings of this study demonstrate the significance of hepatopancreas lectin as a multifunctional defense protein that inhibits the growth of bacteria and fungi.
凝集素是一类多功能蛋白，能够特异性识别并结合细胞表面表达的糖基。由于凝集素在药物靶向和递送方面的潜力，人们对其产生了浓厚的兴趣，从而促使人们去鉴定天然的凝集素。螃蟹被认为是凝集素的丰富来源，因为其先天免疫系统在遇到病原体时会被激活，从而有助于凝集素的产生。尽管螃蟹血淋巴中凝集素的存在已得到充分证实，但关于甲壳类动物重要免疫和消化器官——肝胰腺中凝集素的信息却很少。一种钙依赖性凝集素（75 kDa）已通过生物吸附和胎球蛋白连接的琼脂糖 4B 亲和层析技术从淡水蟹 Oziotelphusa naga 的肝胰腺中被分离纯化。该分离出的肝胰腺凝集素是钙依赖性的，对兔红细胞的凝集活性最高。凝集素的血凝活性可被乳糖、GlcNAc、海藻糖和 NeuAc 等糖有效抑制。与转铁蛋白和脱铁转铁蛋白等唾液酸化的 N-糖基化蛋白相比，胎球蛋白等唾液酸化的 O-糖基化蛋白具有更强的抑制作用。通过对强抑制剂进行去唾液酸化处理，发现红细胞与肝胰腺凝集素的结合能力降低，这表明唾液酸在凝集素-配体相互作用中具有重要意义。纯化的肝胰腺凝集素对金黄色葡萄球菌、肺炎克雷伯菌、奇异变形杆菌、铜绿假单胞菌、大肠杆菌和真菌白色念珠菌和黑曲霉均具有广谱的抗菌活性。本研究的结果表明，肝胰腺凝集素作为一种多功能防御蛋白，具有抑制细菌和真菌生长的作用。
