Developing highly active small molecule ice recrystallization inhibitors based upon C-linked antifreeze glycoprotein analogues
作者:John F. Trant、Robyn A. Biggs、Chantelle J. Capicciotti、Robert N. Ben
DOI:10.1039/c3ra43835j
日期:——
Ice recrystallization during cryopreservation results in a significant amount of cellular damage making compounds that exhibit ice recrystallization inhibition (IRI) activity desirable as a novel class of cryoprotectants. Herein, we report a systematic structure–function study on a previously identified IRI active C-linked antifreeze glycoprotein (C-AFGP) analogue (1). These studies indicate that while C-AFGPs containing three tripeptide repeats exhibit weak IRI activity 5.5 μM, a minimum number of four tripeptide repeats is required for potent IRI activity at this concentration. In addition, the galactosyl–ornithine building block 5 exhibited only moderate activity at 22 mM, but IRI activity was significantly increased upon addition of two glycine units to the C-terminal end of the amino acid bearing the C-linked galactopyranose residue. Finally, we report that conjugation of long alkyl chains (octyl, nonyl and decyl) to the C-linked galactosyl moiety of 1 can furnish IRI active small molecules. The “ideal” hydrocarbon chain length was 10 carbons for potent activity in this series of compounds. Longer hydrocarbon chain lengths dramatically decreased solubilities. The results of this study emphasize the importance of hydrophobic moieties for IRI activity and while consistent with previously reported small molecule carbohydrate-based and lysine-based ice recrystallization inhibitors, is the first example where a large IRI active glycoconjugate has been successfully truncated to small molecule IRI active components.
冰晶再结晶在冷冻保存过程中会造成显著的细胞损伤,使得展现冰晶再结晶抑制(IRI)活性的化合物成为一种新型冷冻保护剂的理想选择。在此,我们报告了一项对先前鉴定的C-连接抗冻糖蛋白(C-AFGP)类似物(1)的系统结构-功能研究。这些研究表明,虽然含有三个肽链重复单元的C-AFGP展现出弱的IRI活性(5.5 μM),但在此浓度下,要求至少四个肽链重复单元以展现强效的IRI活性。此外,半乳糖苷-鸟氨酸构建块5在22 mM时仅表现出中等活性,但当将两个甘氨酸单元添加到带有C-连接半乳糖吡喃糖基残基的氨基酸的C末端时,IRI活性显著增加。最后,我们报告将长烷基链(辛基、壬基和癸基)连接到1的C-连接半乳糖基部分可以生成具有IRI活性的低分子化合物。在这一系列化合物中,"理想"的烃链长度为10个碳,以展现强效活性。更长的烃链长度显著降低了溶解度。本研究的结果强调了疏水基团对IRI活性的关键重要性,虽然与先前报告的基于小分子碳水化合物和赖氨酸的冰晶再结晶抑制剂一致,但这是首次成功将大型IRI活性糖缀合物截短至小分子IRI活性成分的例子。