NO formation by a catalytically self-sufficient bacterial nitric oxide synthase from Sorangium cellulosum
NO formation by a catalytically self-sufficient bacterial nitric oxide synthase from Sorangium cellulosum
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DOI：
10.1073/pnas.0908443106
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发表时间：
2009-09-22
影响因子：
11.1
通讯作者：
Marletta, Michael A.
中科院分区：
文献类型：
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作者：
Agapie, Theodor;Suseno, Sandy;Marletta, Michael A.
一氧化氮 (NO) 在宿主对感染的反应和细胞信号传导中的作用已得到充分证实。 NO 的酶促合成由一氧化氮合酶 (NOS) 催化，利用共底物 O-2 和 NADPH 将精氨酸转化为 NO 和瓜氨酸。哺乳动物 NOS 包含黄素还原酶结构域（FAD 和 FMN）和催化血红素加氧酶结构域（P450 型血红素和四氢生物蝶呤）。细菌 NOS 虽然研究较少，但之前被鉴定为仅包含更复杂的哺乳动物 NOS 的血红素加氧酶结构域。我们在这里报告了来自 Sorangium cellulosum 的 NOS 的表征（全长 scNOS 和加氧酶结构域 scNOSox）。 scNOS 含有催化加氧酶结构域，与哺乳动物 NOS 和其他细菌中发现的结构域类似。然而，与迄今为止报道的其他细菌 NOS 不同，该蛋白含有融合还原酶结构域。 scNOS 还原酶结构域对于整个 NOS 家族来说是独一无二的，因为它利用 2Fe2S 簇进行电子转移。 scNOS 在四氢生物蝶呤或四氢叶酸存在下催化产生 NO 和瓜氨酸。这些结果建立了用于生物 NO 合成的细菌电子转移途径，以及在该反应中使用不同四氢蝶呤辅因子的独特灵活性。
The role of nitric oxide ( NO) in the host response to infection and in cellular signaling is well established. Enzymatic synthesis of NO is catalyzed by the nitric oxide synthases (NOSs), which convert Arg into NO and citrulline using co-substrates O-2 and NADPH. Mammalian NOS contains a flavin reductase domain ( FAD and FMN) and a catalytic heme oxygenase domain (P450-type heme and tetrahydrobiopterin). Bacterial NOSs, while much less studied, were previously identified as only containing the heme oxygenase domain of the more complex mammalian NOSs. We report here on the characterization of a NOS from Sorangium cellulosum ( both full-length, scNOS, and oxygenase domain, scNOSox). scNOS contains a catalytic, oxygenase domain similar to those found in the mammalian NOS and in other bacteria. Unlike the other bacterial NOSs reported to date, however, this protein contains a fused reductase domain. The scNOS reductase domain is unique for the entire NOS family because it utilizes a 2Fe2S cluster for electron transfer. scNOS catalytically produces NO and citrulline in the presence of either tetrahydrobiopterin or tetrahydrofolate. These results establish a bacterial electron transfer pathway used for biological NO synthesis as well as a unique flexibility in using different tetrahydropterin cofactors for this reaction.