Activation of the Class Ib Ribonucleotide Reductase by a Flavodoxin Reductase in Bacillus cereus,Biochemistry

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Activation of the Class Ib Ribonucleotide Reductase by a Flavodoxin Reductase in Bacillus cereus
Biochemistry ( IF 2.9 ) Pub Date : 2016-08-30 00:00:00 , DOI: 10.1021/acs.biochem.6b00699
Marie Lofstad ₁ , Ingvild Gudim ₁ , Marta Hammerstad ₁ , Åsmund Kjendseth Røhr ₂ , Hans-Petter Hersleth ₁

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To reduce ribonucleotides to deoxyribonucleotides, the manganese-bound form of class Ib ribonucleotide reductase (RNR) must be activated via a pathway that involves redox protein(s). The reduced flavoprotein NrdI is an important protein in this pathway, as it reduces dioxygen to superoxide. Superoxide then reacts with the RNR Mn^II₂ site to generate a tyrosyl radical that is required for catalysis. A native NrdI reductase has not yet been identified. We herein demonstrate through kinetic and spectroscopic studies that an endogenous flavodoxin reductase can function as the NrdI reductase in Bacillus cereus. When the flavodoxin reductase reduces NrdI, tyrosyl radical formation in RNR is promoted under aerobic conditions, significantly increasing the radical yield. Thus, a missing piece of the class Ib RNR NrdI redox pathway has finally been identified.

中文翻译：

蜡样芽孢杆菌中黄酮毒素还原酶激活Ib类核糖核苷酸还原酶

为了将核糖核苷酸还原为脱氧核糖核苷酸，Ib类核糖核苷酸还原酶（RNR）的锰结合形式必须通过涉及氧化还原蛋白的途径激活。减少的黄素蛋白NrdI是该途径中的重要蛋白，因为它将双氧还原为超氧化物。然后超氧化物与RNR Mn ^II₂位点反应生成催化所需的酪氨酰基。尚未鉴定出天然的NrdI还原酶。我们在本文中通过动力学和光谱学研究证明内源性黄酮毒素还原酶可以在蜡样芽胞杆菌中充当NrdI还原酶。。当黄酮毒素还原酶还原NrdI时，RNR中有氧条件下酪氨酸基团的形成得到促进，从而显着提高了基团的收率。因此，终于鉴定出Ib RNR NrdI类氧化还原途径的缺失部分。

更新日期：2016-08-30

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