Nitration of a peptide phytotoxin by bacterial nitric oxide synthase
Nitration of a peptide phytotoxin by bacterial nitric oxide synthase
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DOI：
10.1038/nature02504
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发表时间：
2004-05-06
期刊：
影响因子：
64.8
通讯作者：
Loria, R
中科院分区：
文献类型：
--
作者：
Kers, JA;Wach, MJ;Loria, R
在哺乳动物中，一氧化氮（NO）是一种有效的细胞间信号，介导了血压、激素释放、神经传递和高等生物免疫反应的关键方面（1-4）。在低等多细胞生物中发现了与全长哺乳动物一氧化氮合酶（nos）同源的蛋白质(5)。最近，基因组测序表明，一些细菌含有编码NOS截断蛋白的基因；这与细菌提取物中nos样活性的报道是一致的（6,7）。细菌NOSs的生物学功能尚不清楚，但据推测与它们在哺乳动物中的作用类似。在这里，我们描述了植物病原体流肿链霉菌中编码NOS同源物的基因，并揭示了其在植物致病性所需的二肽植物毒素硝化中的作用(8)。细菌NOSs之间的高度相似性表明其在生物合成硝化中具有一般功能；因此，细菌NOSs构成了一类新的酶（9-11）。本研究表明，链霉菌NOS的主要功能与哺乳动物NOS完全不同。令人惊讶的是，哺乳动物NO信号传导和细菌生物合成硝化具有共同的进化起源。
Nitric oxide ( NO) is a potent intercellular signal in mammals that mediates key aspects of blood pressure, hormone release, nerve transmission and the immune response of higher organisms(1-4). Proteins homologous to full-length mammalian nitric oxide synthases (NOSs) are found in lower multicellular organisms(5). Recently, genome sequencing has shown that some bacteria contain genes coding for truncated NOS proteins; this is consistent with reports of NOS-like activities in bacterial extracts(6,7). Biological functions for bacterial NOSs are unknown, but have been presumed to be analogous to their role in mammals. Here we describe a gene in the plant pathogen Streptomyces turgidiscabies that encodes a NOS homologue, and we reveal its role in nitrating a dipeptide phytotoxin required for plant pathogenicity(8). High similarity between bacterial NOSs indicates a general function in biosynthetic nitration; thus, bacterial NOSs constitute a new class of enzymes(9-11). Here we show that the primary function of Streptomyces NOS is radically different from that of mammalian NOS. Surprisingly, mammalian NO signalling and bacterial biosynthetic nitration share an evolutionary origin.