A mechanism for stabilization of membranes at low temperatures by an antifreeze protein
A mechanism for stabilization of membranes at low temperatures by an antifreeze protein
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DOI：
10.1016/s0006-3495(02)75449-0
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发表时间：
2002-02-01
影响因子：
3.4
通讯作者：
Crowe, JH
中科院分区：
文献类型：
--
作者：
Tomczak, MM;Hincha, DK;Crowe, JH
北极鱼、耐寒植物和越冬昆虫产生抗冻蛋白(AFP)，这种蛋白非综合性地降低溶液的冰点，抑制冰晶生长。在体外低温保存过程中，FISH AFP可能通过与细胞膜相互作用来稳定细胞膜和细胞，但其稳定机制尚不清楚。我们在这里表明，在冷藏到非冷冻温度期间，来自极地鱼类的α-螺旋AFP I型抑制了包含不饱和叶绿体半乳糖脂的模型膜的渗漏。其机理包括AFP与双层的结合，这提高了膜的相变温度，并改变了酰基链的分子堆积。我们认为，这种改变的酰基链堆积导致膜的通透性降低。数据表明，多肽和双层之间存在疏水相互作用。此外，我们认为AFP I型在转基因植物中的表达可能对冷敏感植物的热适应具有重要意义。
Polar fish, cold hardy plants, and overwintering insects produce antifreeze proteins (AFPs), which lower the freezing point of solutions noncolligatively and inhibit ice crystal growth. Fish AFPs have been shown to stabilize membranes and cells in vitro during hypothermic storage, probably by interacting with the plasma membrane, but the mechanism of this stabilization has not been clear. We show here that during chilling to nonfreezing temperatures the alpha-helical AFP type I from polar fish inhibits leakage across model membranes containing an unsaturated chloroplast galactolipid. The mechanism involves binding of the AFP to the bilayer, which increases the phase transition temperature of the membranes and alters the molecular packing of the acyl chains. We suggest that this change in acyl chain packing results in the reduced membrane permeability. The data suggest a hydrophobic interaction between the peptide and the bilayer. Further, we suggest that the expression of AFP type I in transgenic plants may be significant for thermal adaptation of chilling-sensitive plants.