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NLP毒性的结构基础
Structural basis for NLP toxicity |
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| 课程网址: |
http://videolectures.net/biophysics2018_lenarcic_nlp_toxicity/
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| 主讲教师: |
Tea Lenarčič
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| 开课单位: |
斯洛文尼亚国家化学研究所
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| 开课时间: |
2018-07-09
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| 课程语种: |
英语
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| 中文简介: |
坏死和乙烯诱导肽1（Nep1）样蛋白（NLP）由几种植物病原细菌、真菌和卵菌分泌。它们在各种双子叶植物中引发叶片坏死和免疫相关反应。我们最近的研究表明，糖基醇磷酰神经酰胺（GIPC）是植物细胞质膜中的一类主要植物鞘脂，是NLP蛋白的靶分子。利用X射线结晶学以及其他生化和生物物理实验进行的结构研究表明，来自植物病原卵菌Pythium aphanidermatum（NLPPya）的NLP蛋白与这些鞘脂的末端己糖部分形成复合物。NLPPya与GIPC头基的结合会引起一些构象变化，例如L2-L3排列的裂缝变宽，镁离子相对于其在无配体NLPPya中的位置向蛋白质中心移动2.9Å，随后是膜附着和宿主细胞裂解。NLPPya蛋白残基的基于结构的点突变预计对膜锚定起关键作用，从而导致植物毒素抗性。这些结果提出了NLPPya膜相互作用早期步骤的模型，并解释了由于GIPC糖苷模块结合到NLPPya的配体结合裂缝中的空间限制，双子叶植物NLP蛋白质的选择性。
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| 课程简介: |
Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by several phytopathogenic bacteria, fungi and oomycetes. They trigger leaf necrosis and immunity-associated responses in various dicotyledonous plants. Our recent studies showed that glycosylinositol phosphorylceramides (GIPC), a major class of plant sphingolipids in plant cell plasma membranes, are target molecules for NLP proteins. Structural studies using X-ray crystallography complemented with other biochemical and biophysical experiments revealed that a NLP protein from the phytopathogenic oomycete Pythium aphanidermatum (NLPPya) forms complexes with terminal hexose moieties of these sphingolipids. NLPPya binding to GIPC head groups induces several conformational changes, such as widening of the L2-L3-lined crevice and a 2.9Å movement of magnesium ion towards the center of the protein relative to its position in ligand-free NLPPya, which is followed by membrane attachment and host cell lysis. Structure based point mutations of residues in NLPPya protein predicted to be crucial for membrane anchoring resulted in plant toxin resistance. These results propose a model of early steps of NLPPya membrane interaction as well as suggest an explanation for selectivity of NLP proteins for dicotyledonous plants due to steric limitations of GIPC glycoside modules binding into a ligand binding cleft of NLPPya.
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| 关 键 词: |
X射线结晶学; 生物物理实验; 双子叶植物NLP蛋白质
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| 课程来源: |
视频讲座网
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| 数据采集: |
2021-11-11：zkj
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| 最后编审: |
2021-11-11：zkj
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| 阅读次数: |
92
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