Reactivity of the nitrogen-centered tryptophanyl radical in the catalysis by the radical SAM enzyme NosL
Reactivity of the nitrogen-centered tryptophanyl radical in the catalysis by the radical SAM enzyme NosL
复制标题
以氮为中心的色氨酸自由基在自由基 SAM 酶 NosL 的催化下的反应性。
DOI：
10.1039/c6cc08869d
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发表时间：
2017-01-07
影响因子：
4.9
通讯作者：
Zhang, Qi
中科院分区：
文献类型：
--
作者：
Qianzhu, Haocheng;Ji, Wenjuan;Zhang, Qi
参与那西肽生物合成的自由基SAM色氨酸（Trp）裂合酶NosL催化两个平行反应，分别将l-Trp转化为3-甲基-2-吲哚酸（MIA）以及脱氢甘氨酸和3-甲基吲哚。这两个平行的反应从一个氮为中心的双羟基自由基中间体发散。在这里，我们报告的内在反应性的研究使用的化学模型研究和DFT计算的dahanyl自由基。本文还详细研究了NosL催化反应中氮中心自由基的形成和裂解动力学。我们的分析解释了NosL的有趣的催化混杂性，并强调了这种酶在实现能量非常不利的转化中发挥的显着作用。
The radical SAM tryptophan (Trp) lyase NosL involved in nosiheptide biosynthesis catalyzes two parallel reactions, converting l-Trp to 3-methyl-2-indolic acid (MIA) and to dehydroglycine and 3-methylindole, respectively. The two parallel reactions diverge from a nitrogen-centered tryptophanyl radical intermediate. Here we report an investigation on the intrinsic reactivity of the tryptophanyl radical using a chemical model study and DFT calculations. The kinetics of the formation and fragmentation of this nitrogen-centered radical in NosL catalysis were also studied in detail. Our analysis explains the intriguing catalytic promiscuity of NosL and highlights the remarkable role this enzyme plays in achieving an energetically highly unfavorable transformation.