Department of Applied Biochemistry, Tokai University, Hiratsuka, Japan.
J Innate Immun. 2010;2(1):24-32. doi: 10.1159/000228160. Epub 2009 Jul 24.
Ficolins are a group of oligomeric lectins with subunits consisting of both collagen-like and fibrinogen-like domains. The majority of ficolins identified in vertebrates and invertebrates to date recognize N-acetylglucosamine (GlcNAc). X-ray crystallographic analysis of human ficolins has shown that the fibrinogen-like domain binds to the N-acetylated moiety. Ficolins in serum are associated with MBL-associated serine protease (MASP). The ficolin-MASP complex binds directly to carbohydrates present on the surface of a variety of Gram-positive and Gram-negative bacteria through ficolin. Binding of the complex initiates complement activation via the lectin pathway, leading to generation of opsonic fragments of complement components, such as C3b, and to lysis of the bacteria by the membrane attack complex. Thus, serum ficolins play an important role in innate immunity.
纤维胶凝蛋白是一组寡聚凝集素，其亚基由胶原样和纤维蛋白原样结构域组成。迄今为止，在脊椎动物和无脊椎动物中发现的大多数纤维胶凝蛋白识别 N-乙酰葡萄糖胺（GlcNAc）。人纤维胶凝蛋白的 X 射线晶体结构分析表明，纤维蛋白原样结构域与 N-乙酰化部分结合。血清中的纤维胶凝蛋白与甘露糖结合凝集素相关丝氨酸蛋白酶（MASP）相关联。纤维胶凝蛋白-MASP 复合物通过纤维胶凝蛋白直接与各种革兰氏阳性和革兰氏阴性细菌表面的碳水化合物结合。复合物的结合通过凝集素途径启动补体激活，导致补体成分的调理片段（如 C3b）的产生，并通过膜攻击复合物导致细菌溶解。因此，血清纤维胶凝蛋白在先天免疫中发挥重要作用。
