Mathevon Carole, Pierrel Fabien, Oddou Jean-Louis, Garcia-Serres Ricardo, Blondin Geneviève, Latour Jean-Marc, Ménage Stéphane, Gambarelli Serge, Fontecave Marc, Atta Mohamed
Commissariat à l'Energie Atomique/Centre National de la Recherche Scientifique/Université Joseph Fourier, Commissariat à l'Energie Atomique/Grenoble, 38054 Grenoble Cedex 09, France.
Proc Natl Acad Sci U S A. 2007 Aug 14;104(33):13295-300. doi: 10.1073/pnas.0704338104. Epub 2007 Aug 6.
MiaE catalyzes the posttranscriptional allylic hydroxylation of 2-methylthio-N-6-isopentenyl adenosine in tRNAs. The Salmonella typhimurium enzyme was heterologously expressed in Escherichia coli. The purified enzyme is a monomer with two iron atoms and displays activity in in vitro assays. The type and properties of the iron center were investigated by using a combination of UV-visible absorption, EPR, HYSCORE, and Mössbauer spectroscopies which demonstrated that the MiaE enzyme contains a nonheme dinuclear iron cluster, similar to that found in the hydroxylase component of methane monooxygenase. This is the first example of an enzyme from this important class of diiron monooxygenases to be involved in the hydroxylation of a biological macromolecule and the second example of a redox metalloenzyme participating in tRNA modification.
MiaE催化转运RNA中2-甲硫基-N6-异戊烯基腺苷的转录后烯丙基羟基化反应。鼠伤寒沙门氏菌的这种酶在大肠杆菌中进行了异源表达。纯化后的酶是一种含有两个铁原子的单体，并且在体外测定中表现出活性。通过结合紫外可见吸收光谱、电子顺磁共振光谱、高分辨电子电子双共振光谱和穆斯堡尔光谱对铁中心的类型和性质进行了研究，结果表明MiaE酶含有一个非血红素双核铁簇，类似于在甲烷单加氧酶的羟化酶组分中发现的铁簇。这是这类重要的双铁单加氧酶中首个参与生物大分子羟基化反应的酶的例子，也是参与转运RNA修饰的氧化还原金属酶的第二个例子。
