Molecular basis for functional diversity among microbial Nep1-like proteins
Molecular basis for functional diversity among microbial Nep1-like proteins
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DOI：
10.1371/journal.ppat.1007951
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发表时间：
2019-09-01
期刊：
影响因子：
6.7
通讯作者：
Anderluh, Gregor
中科院分区：
文献类型：
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作者：
Lenarcic, Tea;Pirc, Katja;Anderluh, Gregor
坏死和乙烯诱导肽1(NEP1)样蛋白(NLP)由多种植物病原微生物分泌。当它们与植物鞘磷脂糖肌醇磷酸神经酰胺(GIPC)结合时，它们会在各种优树植物中引发坏死。有趣的是，专性生物滋养菌阿拉伯透明孢子菌的HaNLP3不会导致坏死。我们测定了HaNLP3的晶体结构，表明它采用NLP折叠。然而，GIPC头基结合腔周围环的构象不同于细胞毒性透明腐霉NLPPya的构象。从Mu S-Long分子动力学(MD)模拟中提取的基本动力学表明，相对于有毒的NLP，HaNLP3中GIPC结合空腔的构象可塑性有限。这可能排除了HaNLP3与GIPC的结合，这是缺乏毒性的根本原因。这项研究表明，关键蛋白质区域的突变会导致同一蛋白质支架内无毒和有毒表型之间的转换。总之，这些数据提供了蛋白质灵活性是有毒NLP的一个显著特征的证据，并突出了生物营养植物病原菌利用的无毒NLP潜在功能多样化的结构决定因素。作者概述陆生植物的根际和叶圈是许多微生物的家园，其中许多微生物在与植物结合的特定阶段具有潜在的致病性。病原体使用不同的途径穿透物理屏障，以不同的生活方式定植寄主植物。NLP类蛋白广泛存在于真菌、细菌、卵菌等原核生物和真核生物中，可侵染马铃薯、番茄、大豆、烟草等多种作物，对世界范围内的农业生产构成重大威胁。结果表明，NLP是一种细胞溶解毒素，通过与植物膜鞘磷脂受体结合而导致质膜渗漏。有趣的是，几种半生物营养型和专性生物营养型病原菌也可以分泌无毒的NLP蛋白。本研究提供了一个非细胞毒性的HaNLP3蛋白的结构和功能特征，可以解释这些蛋白是如何在不同生活方式的各种病原体中进化出一系列新的功能的。
Necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) are secreted by several phytopathogenic microorganisms. They trigger necrosis in various eudicot plants upon binding to plant sphingolipid glycosylinositol phosphorylceramides (GIPC). Interestingly, HaNLP3 from the obligate biotroph oomycete Hyaloperonospora arabidopsidis does not induce necrosis. We determined the crystal structure of HaNLP3 and showed that it adopts the NLP fold. However, the conformations of the loops surrounding the GIPC headgroup-binding cavity differ from those of cytotoxic Pythium aphanidermatum NLPPya. Essential dynamics extracted from mu s-long molecular dynamics (MD) simulations reveals a limited conformational plasticity of the GIPC-binding cavity in HaNLP3 relative to toxic NLPs. This likely precludes HaNLP3 binding to GIPCs, which is the underlying reason for the lack of toxicity. This study reveals that mutations at key protein regions cause a switch between non-toxic and toxic phenotypes within the same protein scaffold. Altogether, these data provide evidence that protein flexibility is a distinguishing trait of toxic NLPs and highlight structural determinants for a potential functional diversification of non-toxic NLPs utilized by biotrophic plant pathogens.Author summary The rhizosphere and phyllosphere of terrestrial plants are home to a number of microorganisms, many of which are potentially pathogenic at certain stages during their associations with plants. The pathogens use diverse routes to penetrate physical barriers and colonize host plants with different lifestyles. Necrosis and ethylene inducing peptide 1 (Nep1)-like proteins (NLPs) are widely distributed among prokaryotic and eukaryotic organisms, like fungi, bacteria and oomycetes, and may infect a range of different crops, such as potato, tomato, soybean and tobacco, thus posing major threat to agriculture worldwide. It was shown that NLPs function as cytolytic toxins that induce plasma membrane leakage by binding to plant membrane sphingolipid receptor. Interestingly, non-toxic NLP proteins can also be secreted by several hemibiotrophic and obligate biotrophic pathogens. This study provides a structural and functional characterization of a non-cytotoxic HaNLP3 protein from Hyaloperonospora arabidopsidis that could explain how these proteins evolved a range of new functions in variety of pathogens with different lifestyles.