Nitric Oxide Activation by caa3 Oxidoreductase from Thermus thermophiles
Nitric Oxide Activation by caa3 Oxidoreductase from Thermus thermophiles
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嗜热栖热菌的 caa3 氧化还原酶激活一氧化氮
DOI：
10.1039/c5cp01013f
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发表时间：
2015
影响因子：
3.3
通讯作者：
C. Varotsis
中科院分区：
文献类型：
--
作者：
T. Ohta;T. Soulimane;T. Kitagawa;C. Varotsis
利用可见和紫外共振拉曼光谱研究了嗜热栖热菌细胞色素caa 3与NO的相互作用。我们发现，次硝酸根（HO-NN-O）−与血红素a3物种（νNN = 1330 cm−1）结合，在caa 3-氧化还原酶的氧化血红素a3 Fe/CuB双核中心形成高自旋复合物。在没有血红素a3 Fe 2 +-NO形成的情况下，NN键形成所需的电子来自于由NO自动还原CuB，产生亚硝酸盐。随着次亚硝酸盐中间体的鉴定，好氧呼吸和细菌反硝化作用共同发生的假设得到了充分的支持，NO的2 e −/2 H+还原为N2 O的机制可以更确定地描述。
Visible and UV-resonance Raman spectroscopy was employed to investigate the reaction of NO with cytochrome caa3 from Thermus thermophilus. We show the formation of the hyponitrite (HO–NN–O)− bound to the heme a3 species (νNN = 1330 cm−1) forming a high spin complex in the oxidized heme a3 Fe/CuB binuclear center of caa3-oxidoreductase. In the absence of heme a3 Fe2+–NO formation, the electron required for the formation of the NN bond originates from the autoreduction of CuB by NO, producing nitrite. With the identification of the hyponitrite intermediate the hypothesis of a common phylogeny of aerobic respiration and bacterial denitrification is fully supported and the mechanism for the 2e−/2H+ reduction of NO to N2O can be described with more certainty.