Characterization of the norB gene, encoding nitric oxide reductase, in the nondenitrifying cyanobacterium Synechocystis sp strain PCC6803
Characterization of the norB gene, encoding nitric oxide reductase, in the nondenitrifying cyanobacterium Synechocystis sp strain PCC6803
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DOI：
10.1128/aem.68.2.668-672.2002
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发表时间：
2002-02-01
影响因子：
4.4
通讯作者：
Cramm, R
中科院分区：
文献类型：
--
作者：
Büsch, A;Friedrich, B;Cramm, R
编码推定的一氧化氮还原酶的norB基因存在于非硝化蓝细菌集胞藻属菌株PCC 6803的基因组中。该基因产物属于喹啉氧化单亚基类的一氧化氮还原酶，最近发现的细菌真养罗尔斯通氏菌。一氧化氮还原酶阴性的R.用来自集胞藻的norB处理的真养藻恢复了一氧化氮还原酶活性。与减少甲萘醌作为电子供体，每分钟每毫克蛋白质的酶活性为101毫摩尔的NO获得与集胞藻野生型细胞的膜馏分。几乎没有一氧化氮还原酶活性存在于一个norB阴性突变集胞藻。这种突变体的生长细胞对NO比野生型细胞更敏感，表明一氧化氮还原酶的存在下是有益的集胞藻时，细胞暴露于NO。氯霉素乙酰转移酶报告基因的转录融合构建监测norB表达集胞藻。norB的转录没有增强通过添加NO生成剂硝普钠。
A norB gene encoding a putative nitric oxide reductase is present in the genome of the nondenitrifying cyanobacterium Synechocystis sp. strain PCC6803. The gene product belongs to the quinol-oxidizing single-subunit class of nitric oxide reductases, discovered recently in the denitrifier Ralstonia eutropha. Heterologous complementation of a nitric oxide reductase-negative mutant of R. eutropha with norB from Synechocystis restored nitric oxide reductase activity. With reduced menadione as the electron donor, an enzymatic activity of 101 mmol of NO per min per mg of protein was obtained with membrane fractions of Synechocystis wild-type cells. Virtually no nitric oxide reductase activity was present in a norB-negative mutant of Synechocystis. Growing cells of this mutant are more sensitive toward NO than wild-type cells, indicating that the presence of a nitric oxide reductase is beneficial for Synechocystis when the cells are exposed to NO. Transcriptional fusions with the chloramphenicol acetyltransferase reporter gene were constructed to monitor norB expression in Synechocystis. Transcription of norB was not enhanced by the addition of the NO-generating agent sodium nitroprusside.