Tateno Hiroaki, Nakamura-Tsuruta Sachiko, Hirabayashi Jun
Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Ibaraki 305-8568, Japan.
Glycobiology. 2009 May;19(5):527-36. doi: 10.1093/glycob/cwp016. Epub 2009 Feb 13.
Lens culinaris lectin (LCA) is a useful probe for the detection in serum of a core-fucosylated alpha-fetoprotein, called AFP-L3 fraction, which is a well-known marker for the diagnosis and prognosis of hepatocellular carcinoma. Here we performed a systematic quantitative interaction analysis of LCA and its close homolog, Pisum sativum lectin (PSA), by frontal affinity chromatography with 143 pyridylaminated (PA) glycans including a series of core-fucosylated glycans. Both lectins showed binding affinity to core-fucosylated, mono- and bi-antennary N-glycans, but not to their tri- and tetra-antennary forms, indicating that the addition of the GlcNAc residue at the N-acetylglucosaminyltransferase IV position abrogates the binding affinity. However, their specificities are distinguishable: while LCA showed the highest affinity to the core-fucosylated, agalactosylated, bi-antennary N-glycan (K(a)=1.1 x 10(5) M(-1)), PSA showed the highest affinity to the core-fucosylated, trimannosyl structure (K(a)=1.2 x 10(5) M(-1)). Glycan-binding specificities of LCA and PSA were also analyzed by glycoconjugate microarray compared to other core-fucose-binding lectins from Aspergillus oryzae (AOL) and Aleuria auratia (AAL). LCA and PSA bound specifically to core fucose, whereas AOL and AAL exhibited broad specificity to fucosylated glycans. These results explain why LCA is appropriate as a specific probe for AFP-L3, which mainly contains a core-fucosylated, biantennary N-glycan, but not its highly branched forms.
菜豆凝集素（LCA）是一种用于检测血清中核心岩藻糖基化甲胎蛋白（称为AFP-L3组分）的有用探针，AFP-L3是肝细胞癌诊断和预后的著名标志物。在此，我们通过前沿亲和色谱法，使用143种包括一系列核心岩藻糖基化聚糖的吡啶基胺化（PA）聚糖，对LCA及其紧密同源物豌豆凝集素（PSA）进行了系统的定量相互作用分析。两种凝集素均对核心岩藻糖基化的单天线和双天线N-聚糖表现出结合亲和力，但对其三天线和四天线形式则无结合亲和力，这表明在N-乙酰葡糖胺基转移酶IV位置添加GlcNAc残基会消除结合亲和力。然而，它们的特异性是可区分的：LCA对核心岩藻糖基化、无半乳糖的双天线N-聚糖表现出最高亲和力（K(a)=1.1 x 10(5) M(-1)），而PSA对核心岩藻糖基化的三甘露糖基结构表现出最高亲和力（K(a)=1.2 x 10(5) M(-1)）。与来自米曲霉（AOL）和橙黄网柄菌（AAL）的其他核心岩藻糖结合凝集素相比，还通过糖缀合物微阵列分析了LCA和PSA的聚糖结合特异性。LCA和PSA特异性结合核心岩藻糖，而AOL和AAL对岩藻糖基化聚糖表现出广泛的特异性。这些结果解释了为什么LCA适合作为AFP-L3的特异性探针，AFP-L3主要包含核心岩藻糖基化的双天线N-聚糖，而不是其高度分支的形式。
