The K-Segment of Maize DHN1 Mediates Binding to Anionic Phospholipid Vesicles and Concomitant Structural Changes
The K-Segment of Maize DHN1 Mediates Binding to Anionic Phospholipid Vesicles and Concomitant Structural Changes
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DOI：
10.1104/pp.109.136697
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发表时间：
2009-07-01
期刊：
影响因子：
7.4
通讯作者：
Close, Timothy J.
中科院分区：
文献类型：
--
作者：
Koag, Myong-Chul;Wilkens, Stephan;Close, Timothy J.
脱氢蛋白（Dehydrins, DHNs；胚胎发育晚期丰富的D11家族）是一个本质上非结构化的植物蛋白家族，在种子发育后期和营养组织中积累，经受缺水、盐度、低温或脱落酸处理。我们先前证明，玉米（Zea mays） dhn优先结合阴离子磷脂囊泡；这种结合伴随着蛋白质螺旋度的增加，十二烷基硫酸钠可以诱导蛋白质螺旋度的增加。所有dnn至少包含一个“k段”，这是一个富含赖氨酸的15个氨基酸的一致序列。预计k段形成A2类两亲α -螺旋，这是一种已知与膜和蛋白质相互作用的结构元件。本研究制备了玉米DHN1的3个k段缺失蛋白。脂质囊泡结合实验表明，与阴离子磷脂囊泡结合需要k -片段，并且采用k -片段的α -螺旋度是dhn与阴离子磷脂囊泡或十二烷基硫酸钠结合时构象变化的主要原因。结构的采用可能有助于在压力条件下稳定细胞成分，包括膜。
Dehydrins (DHNs; late embryogenesis abundant D11 family) are a family of intrinsically unstructured plant proteins that accumulate in the late stages of seed development and in vegetative tissues subjected to water deficit, salinity, low temperature, or abscisic acid treatment. We demonstrated previously that maize (Zea mays) DHNs bind preferentially to anionic phospholipid vesicles; this binding is accompanied by an increase in alpha-helicity of the protein, and adoption of alpha-helicity can be induced by sodium dodecyl sulfate. All DHNs contain at least one "K-segment," a lysine-rich 15-amino acid consensus sequence. The K-segment is predicted to form a class A2 amphipathic alpha-helix, a structural element known to interact with membranes and proteins. Here, three K-segment deletion proteins of maize DHN1 were produced. Lipid vesicle-binding assays revealed that the K-segment is required for binding to anionic phospholipid vesicles, and adoption of alpha-helicity of the K-segment accounts for most of the conformational change of DHNs upon binding to anionic phospholipid vesicles or sodium dodecyl sulfate. The adoption of structure may help stabilize cellular components, including membranes, under stress conditions.