NO dioxygenase activity in hemoglobins is ubiquitous in vitro, but limited by reduction in vivo.
NO dioxygenase activity in hemoglobins is ubiquitous in vitro, but limited by reduction in vivo.
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DOI：
10.1371/journal.pone.0002039
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发表时间：
2008-04-30
期刊：
影响因子：
3.7
通讯作者：
Hargrove MS
中科院分区：
文献类型：
--
作者：
Smagghe BJ;Trent JT 3rd;Hargrove MS
基因组学已经产生了数百个新的血红蛋白序列，几乎在每一个活着的有机体中都有例子。许多重组蛋白的结构和生化特征揭示了诸如氧结合和无双加氧等反应，这些反应在血红蛋白超家族中似乎是普遍的，无论它们是否与生理功能有关。尽管人们对几乎在每种动植物中都存在的“六配位”血红蛋白有相当大的关注，但在任何物种中都没有明确的生理作用(S)。关于它们功能的一个流行且相关的假说是对NO的保护作用。在这里，我们测试了来自植物(大米血红蛋白)、动物(脑红蛋白和细胞球蛋白)和细菌(聚球藻血红蛋白)的六配位血红蛋白的综合表示，与肌红蛋白相比，它们清除NO的能力。我们的实验包括体外比较NO的双氧合作用、铁的NO结合、NO诱导的还原、人工还原系统对NO的清除，以及在大肠杆菌中替代已知的NO清除剂(黄色素)的能力。我们的结论是，这些测试都没有显示出任何明显的倾向于不清除hxHbs的作用，但任何血红蛋白都可能在存在血红素铁再还原机制的情况下发挥这一作用。因此，未来测试HBS在清除NO中的作用的研究将更多地受益于同源还原酶的鉴定，而不是体外分析NO和O2的结合。
Genomics has produced hundreds of new hemoglobin sequences with examples in nearly every living organism. Structural and biochemical characterizations of many recombinant proteins reveal reactions, like oxygen binding and NO dioxygenation, that appear general to the hemoglobin superfamily regardless of whether they are related to physiological function. Despite considerable attention to “hexacoordinate” hemoglobins, which are found in nearly every plant and animal, no clear physiological role(s) has been assigned to them in any species. One popular and relevant hypothesis for their function is protection against NO. Here we have tested a comprehensive representation of hexacoordinate hemoglobins from plants (rice hemoglobin), animals (neuroglobin and cytoglobin), and bacteria (Synechocystis hemoglobin) for their abilities to scavenge NO compared to myoglobin. Our experiments include in vitro comparisons of NO dioxygenation, ferric NO binding, NO-induced reduction, NO scavenging with an artificial reduction system, and the ability to substitute for a known NO scavenger (flavohemoglobin) in E. coli. We conclude that none of these tests reveal any distinguishing predisposition toward a role in NO scavenging for the hxHbs, but that any hemoglobin could likely serve this role in the presence of a mechanism for heme iron re-reduction. Hence, future research to test the role of Hbs in NO scavenging would benefit more from the identification of cognate reductases than from in vitro analysis of NO and O2 binding.
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影响因子：
46.9
作者：
Doherty, DH;Doyle, MP;Lemon, DD
通讯作者：
Lemon, DD
DOI：
10.1006/bbrc.2001.5614
发表时间：
2001-09-21
影响因子：
3.1
作者：
Awenius, C;Hankeln, T;Burmester, T
通讯作者：
Burmester, T
影响因子：
13.8
作者：
Brunori, M
通讯作者：
Brunori, M
DOI：
10.1073/pnas.95.18.10378
发表时间：
1998-09-01
影响因子：
11.1
作者：
Gardner, PR;Gardner, AM;Salzman, AL
通讯作者：
Salzman, AL
影响因子：
4.3
作者：
Dordas, C;Hasinoff, BB;Hill, RD
通讯作者：
Hill, RD