The importance of hydration for inhibiting ice recrystallization with C-linked antifreeze glycoproteins
The importance of hydration for inhibiting ice recrystallization with C-linked antifreeze glycoproteins
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DOI：
10.1021/ja7103262
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发表时间：
2008-03-12
影响因子：
15
通讯作者：
Ben, Robert N.
中科院分区：
文献类型：
--
作者：
Czechura, Pawel;Tam, Roger Y.;Ben, Robert N.
水化在调节溶液构象、分子识别和寡糖、蛋白质和核苷酸的生物活性中的作用被广泛认识，但在研究许多生物过程（如生物防冻剂抑制冰生长的机制）时常常被忽视。我们已经研究了功能性C-连接的抗冻糖蛋白（AFGP）类似物1-4使用一系列的碳水化合物的构型和重结晶抑制（RI）活性之间的关系。虽然类似物1-4没有显示出任何热滞后（TH）活性，但1确实显示出弱的动态冰成形，表明该化合物具有与冰晶格相互作用的能力。D-甘露糖和D-塔罗糖类似物（分别为3和4）显示出非常弱的RI活性，平均最大粒度值与磷酸盐缓冲盐水（阴性对照）相似。D-葡萄糖类似物2表现出中等的RI活性，而D-半乳糖类似物1是具有与天然AFGP 8相当的RI活性的最有效的类似物。这些结果表明，在C-连接的AFGP类似物的碳水化合物部分的配置是非常重要的，并调制重结晶抑制活性。这似乎可能是每个C-连接的吡喃糖的水合作用的差异改变了碳水化合物部分与过冷本体水的三维氢键网络的相容性。因此，与将水分子转移到冰格相关联的能量发生变化，并且可以导致冰生长的抑制。这些结果强调了继续研究的重要性，以进一步阐明水化作用在抗冻活性。
The role of hydration in modulating solution conformation, molecular recognition, and biological activity of oligosaccharides, proteins, and nucleotides is widely recognized but is often neglected when investigating many biological processes such as the mechanism by which biological antifreezes inhibit the growth of ice. We have investigated the relationship between carbohydrate configuration and recrystallization-inhibition (RI) activity in functional C-linked antifreeze glycoprotein (AFGP) analogues using a series of analogues 1-4. While analogues 1-4 did not show any thermal hysteresis (TH) activity, 1 did exhibit weak dynamic ice shaping indicating that this compound had the ability to interact with the ice lattice. The D-mannose and D-talose analogues (3 and 4, respectively) exhibited very weak RI activity with mean largest grain size values similar to phosphate buffered saline, the negative control. D-Glucose analogue 2 exhibited moderate RI activity while D-galactose analogue 1 was the most potent analogue with RI activity comparable to the native AFGP 8. These results suggest that the configuration of the carbohydrate moiety in C-linked AFGP analogues is extremely important and modulates recrystallization-inhibition activity. It seems likely that differences in hydration for each C-linked pyranose alter the compatibility of the carbohydrate moiety with the three-dimensional hydrogen-bonded network of supercooled bulk water. Consequently, the energy associated with transferring a water molecule to the ice lattice changes and can result in inhibition of ice growth. These results emphasize the importance of continued studies to further elucidate the role of hydration in antifreeze activity.