Inhibition of cryoaggregation of phospholipid liposomes by an Arabidopsis intrinsically disordered dehydrin and its K-segment
Inhibition of cryoaggregation of phospholipid liposomes by an Arabidopsis intrinsically disordered dehydrin and its K-segment
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DOI：
10.1016/j.colsurfb.2021.112286
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发表时间：
2021-12-18
影响因子：
5.8
通讯作者：
Hara, Masakazu
中科院分区：
文献类型：
--
作者：
Kimura, Yuki;Ohkubo, Tomohiro;Hara, Masakazu
脱氢蛋白是一种内在无序的蛋白质，与植物的耐寒性有关。尽管人们认为脱水剂可以在寒冷条件下保护生物膜，但其潜在的保护机制尚未得到证实。本文报道了拟南芥脱氢蛋白AtHIRD11在冷冻和解冻后抑制磷脂脂质体的聚集。与海藻糖、脯氨酸和聚乙二醇等低温保护剂相比，AtHIRD11具有更强的低温聚集预防活性。氨基酸序列分割分析表明，AtHIRD11的k片段抑制磷脂酰胆碱脂质体的低温聚集，而其他片段则无此作用。这表明在所有脱水剂中保守的k片段都可能是脱水剂的低温保护位点。典型的k段（简称TypK）序列的氨基酸替换表明，疏水氨基酸和带电荷氨基酸都是PC脂质体防止低温聚集活性所必需的。TypK的氨基酸洗牌显著降低了冷冻保护活性。虽然TypK在溶液中不与PC脂质体结合，但脂质体的加入减少了其在拥挤条件下的无序含量。总之，这些结果表明，脱水剂通过保守的k -片段保护生物膜，这些k -片段的序列被优化为具有低温保护活性。
Dehydrin is an intrinsically disordered protein involved in the cold tolerance of plants. Although dehydrins have been thought to protect biomembranes under cold conditions, the underlying protective mechanism has not been confirmed. Here we report that Arabidopsis dehydrin AtHIRD11 inhibited the aggregation of phospholipid liposomes after freezing and thawing. AtHIRD11 showed significantly greater cryoaggregation-prevention activity than cryoprotective agents such as trehalose, proline, and polyethylene glycols. Amino acid sequence segmentation analysis indicated that the K-segment of AtHIRD11 inhibited the cryoaggregation of phosphatidylcholine (PC) liposomes but other segments did not. This showed that K-segments conserved in all dehydrins were likely to be the cryoprotective sites of dehydrins. Amino acid replacement for a typical K-segment (TypK for short) sequence demonstrated that both hydrophobic and charged amino acids were required for the cryoaggregationprevention activity of PC liposomes. The amino acid shuffling of TypK remarkably reduced cryoprotective activity. Although TypK did not bind to PC liposomes in solution, the addition of liposomes reduced its disordered content under crowded conditions. Together, these results suggested that dehydrins protected biomembranes via conserved K-segments whose sequences were optimized for cryoprotective activities.