Yen Meng-Hsiu, Wu Albert M, Yang Zhangung, Gong Yu-Ping, Chang En-Tzu
Glyco-Immunochemistry Research Labortory, Institute of Molecular and Cellular Biology, College of Medicine, Chang Gung University, Tao-yuan, Taiwan.
Biochim Biophys Acta. 2011 Feb;1810(2):139-49. doi: 10.1016/j.bbagen.2010.10.007. Epub 2010 Nov 2.
Lactoferrin is an iron-binding protein belonging to the transferrin family. In addition to iron homeostasis, lactoferrin is also thought to have anti-microbial, anti-inflammatory, and anticancer activities. Previous studies showed that all lactoferrins are glycosylated in the human body, but the recognition roles of their carbohydrate glycotopes have not been well addressed.
The roles of human and bovine lactoferrins involved in lectin-N-glycan recognition processes were analyzed by enzyme-linked lectinosorbent assay with a panel of applied and microbial lectins.
Both native and asialo human/bovine lactoferrins reacted strongly with four Man-specific lectins - Concanavalia ensiformis agglutinin, Morniga M, Pisum sativum agglutinin, and Lens culinaris lectin. They also reacted well with PA-IIL, a LFuc>Man-specific lectin isolated from Pseudomonas aeruginosa. Both human and bovine lactoferrins also recognized a sialic acid specific lectin-Sambucus nigra agglutinin, but not their asialo products. Both native and asialo bovine lactoferrins, but not the human ones, exhibited strong binding with a GalNAc>Gal-specific lectin-Wisteria floribunda agglutinin. Human native lactoferrins and its asialo products bound well with four Gal>GalNAc-specific type-2 ribosome inactivating protein family lectins-ricin, abrin-a, Ricinus communis agglutinin 1, and Abrus precatorius agglutinin (APA), while the bovine ones reacted only with APA.
This study provides essential knowledge regarding the different roles of bioactive sites of lactoferrins in lectin-N-glycan recognition processes.
乳铁蛋白是一种属于转铁蛋白家族的铁结合蛋白。除了铁稳态外，乳铁蛋白还被认为具有抗菌、抗炎和抗癌活性。先前的研究表明，所有乳铁蛋白在人体内都进行了糖基化修饰，但其碳水化合物糖基表位的识别作用尚未得到充分研究。
通过酶联凝集素吸附测定法，使用一组应用凝集素和微生物凝集素，分析人乳铁蛋白和牛乳铁蛋白在凝集素 - N - 聚糖识别过程中的作用。
天然型和去唾液酸型人/牛乳铁蛋白均与四种甘露糖特异性凝集素——刀豆球蛋白A、Morniga M、豌豆凝集素和扁豆凝集素发生强烈反应。它们也与从铜绿假单胞菌中分离出的一种LFuc>Man特异性凝集素PA-IIL反应良好。人乳铁蛋白和牛乳铁蛋白均能识别一种唾液酸特异性凝集素——黑接骨木凝集素，但不能识别其去唾液酸产物。天然型和去唾液酸型牛乳铁蛋白（而非人乳铁蛋白）与一种GalNAc>Gal特异性凝集素——紫藤凝集素表现出强烈结合。人天然乳铁蛋白及其去唾液酸产物与四种Gal>GalNAc特异性2型核糖体失活蛋白家族凝集素——蓖麻毒素、相思子毒素-a、蓖麻凝集素1和相思子凝集素（APA）结合良好，而牛乳铁蛋白仅与APA反应。
本研究提供了关于乳铁蛋白生物活性位点在凝集素 - N - 聚糖识别过程中不同作用的重要知识。
