THE RHIZOBIUM NODULATION GENE NODO ENCODES A CA-2+-BINDING PROTEIN THAT IS EXPORTED WITHOUT N-TERMINAL CLEAVAGE AND IS HOMOLOGOUS TO HEMOLYSIN AND RELATED PROTEINS
THE RHIZOBIUM NODULATION GENE NODO ENCODES A CA-2+-BINDING PROTEIN THAT IS EXPORTED WITHOUT N-TERMINAL CLEAVAGE AND IS HOMOLOGOUS TO HEMOLYSIN AND RELATED PROTEINS
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DOI：
10.1002/j.1460-2075.1990.tb08117.x
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发表时间：
1990-02-01
期刊：
影响因子：
11.4
通讯作者：
DOWNIE, JA
中科院分区：
文献类型：
--
作者：
ECONOMOU, A;HAMILTON, WDO;DOWNIE, JA
豌豆和豌豆等豆科植物的结瘤和寄主特异性识别。是由豆科根瘤菌生物群的结瘤(Nod)基因编码的。其中一个基因NoDo已被证明编码一种输出的蛋白质，该蛋白质包含一个九个氨基酸结构域的多个串联重复序列。该结构域被发现与一组细菌输出蛋白的重复序列同源，这些蛋白包括溶血素、环溶素、白毒素和两种蛋白酶。这些蛋白质是由一种不涉及N末端信号肽的机制分泌的。在诱导表达nod基因的根瘤菌的生长培养液中存在NoDo蛋白，对纯化的蛋白进行部分蛋白质序列分析表明，输出蛋白没有N端切割。有研究表明，溶血素的内部重复结构域可能参与了钙离子介导的红细胞结合，我们发现NoDo蛋白可以结合45Ca2+。有人认为，NoDo蛋白可能以一种依赖于钙离子的方式直接与植物根细胞相互作用，从而介导了根瘤菌与寄主豆类之间识别的早期阶段。
Nodulation and host-specific recognition of legumes such as peas and Vicia spp. are encoded by the nodulation (nod) genes of Rhizobium Leguminosarum biovar viciae. One of these genes, nodO, has been shown to encode an exported protein that contains a multiple tandem repeat of a nine amino acid domain. This domain was found to be homologous to repeated sequences in a group of bacterial exported proteins that includes haemolysin, cyclolysin, leukotoxin and two proteases. These proteins are secreted by a mechanism that does not involve an N-terminal signal peptide. The NodO protein is present in the growth medium of Rhizobium bacteria induced for nod gene exprssion, and partial protein sequencing of the purified protein showed that there is no N-terminal cleavage of the exported protein. It has been suggested that the internally repeated domain of haemolysin may be involved in Ca2+-mediated binding to erythrocytes and we show that the NodO protein can bind 45Ca2+. It is proposed that the NodO protein may interact directly with plant root cells in a Ca2+-dependent way, thereby mediating an early stage in the recognition that occurs between Rhizobium and is host legume.