Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan.
FEBS Lett. 2013 Nov 15;587(22):3620-5. doi: 10.1016/j.febslet.2013.08.046. Epub 2013 Sep 10.
A fungal galectin from Agrocybe cylindracea (ACG) exhibits broad binding specificity for β-galactose-containing glycans. We determined the crystal structures of wild-type ACG and the N46A mutant, with and without glycan ligands. From these structures and a saccharide-binding analysis of the N46A mutant, we revealed that a conformational change of a unique insertion sequence containing Asn46 provides two binding modes for ACG, and thereby confers broad binding specificity. We propose that the unique sequence provides these two distinct glycan-binding modes by an induced-fit mechanism.
一种来自柱状田头菇（Agrocybe cylindracea）的真菌半乳凝素（ACG）对含有β-半乳糖的聚糖表现出广泛的结合特异性。我们测定了野生型 ACG 及其 N46A 突变体与和不与糖配体结合的晶体结构。通过这些结构以及对 N46A 突变体的糖结合分析，我们揭示了包含 Asn46 的独特插入序列的构象变化为 ACG 提供了两种结合模式，从而赋予了其广泛的结合特异性。我们提出，该独特序列通过诱导契合机制提供了这两种截然不同的聚糖结合模式。
