Despite its natural abundance in lenses of vertebrates the physiological function(s) of the galectin-related inter-fiber protein (GRIFIN) is (are) still unclear. The same holds true for the significance of the unique interspecies (fish/birds vs mammals) variability in the capacity to bind lactose. In solution, ultracentrifugation and small angle X-ray scattering (at concentrations up to 9 mg/mL) characterize the protein as compact and stable homodimer without evidence for aggregation. The crystal structure of chicken (C-)GRIFIN at seven pH values from 4.2 to 8.5 is reported, revealing compelling stability. Binding of lactose despite the Arg71Val deviation from the sequence signature of galectins matched the otherwise canonical contact pattern with thermodynamics of an enthalpically driven process. Upon lactose accommodation, the side chain of Arg50 is shifted for hydrogen bonding to the 3-hydroxyl of glucose. No evidence for a further ligand-dependent structural alteration was obtained in solution by measuring hydrogen/deuterium exchange mass spectrometrically in peptic fingerprints. The introduction of the Asn48Lys mutation, characteristic for mammalian GRIFINs that have lost lectin activity, lets labeled C-GRIFIN maintain capacity to stain tissue sections. Binding is no longer inhibitable by lactose, as seen for the wild-type protein. These results establish the basis for detailed structure-activity considerations and are a step to complete the structural description of all seven members of the galectin network in chicken.

尽管它的天然丰度在脊椎动物透镜的生理功能（多个）克alectin- ř兴高采烈我nter- ˚F IBER prote在（GRIFIN）尚不清楚。乳糖结合能力的独特种间差异（鱼/鸟与哺乳动物）的重要性也是如此。在溶液中，超速离心和小角度X射线散射（浓度高达9 mg / mL）将蛋白质表征为紧凑而稳定的同型二聚体，而没有聚集的迹象。据报道，鸡（C-）GRIFIN在pH值为4.2至8.5的七个pH值下具有晶体结构，显示出令人信服的稳定性。尽管有Arg71Val偏离了半乳凝素的序列标记，但乳糖的结合使原本的典型接触方式与焓驱动过程的热力学相匹配。乳糖适应后，Arg50的侧链发生移位，以使氢键合到葡萄糖的3-羟基上。通过在消化性指纹图中用光谱法测量氢/氘交换质量，未获得溶液中进一步依赖配体的结构改变的证据。Asn48Lys突变的引入是失去凝集素活性的哺乳动物GRIFIN的特征，使标记的C-GRIFIN保持了对组织切片进行染色的能力。如野生型蛋白所见，结合不再被乳糖抑制。这些结果为详细的结构活性考虑奠定了基础，并且是完成鸡半乳糖凝集素网络的所有七个成员的结构描述的步骤。让标记的C-GRIFIN保持对组织切片染色的能力。如野生型蛋白所见，结合不再被乳糖抑制。这些结果为详细的结构活性考虑奠定了基础，并且是完成鸡半乳糖凝集素网络的所有七个成员的结构描述的步骤。让标记的C-GRIFIN保持对组织切片染色的能力。如野生型蛋白所见，结合不再被乳糖抑制。这些结果为详细的结构活性考虑奠定了基础，并且是完成鸡半乳糖凝集素网络的所有七个成员的结构描述的步骤。