Moe Luke A, Bingman Craig A, Wesenberg Gary E, Phillips George N, Fox Brian G
Department of Biochemistry, University of Wisconsin-Madison, USA.
Acta Crystallogr D Biol Crystallogr. 2006 May;62(Pt 5):476-82. doi: 10.1107/S0907444906006056. Epub 2006 Apr 19.
The structure of the Rieske-type ferredoxin (T4moC) from toluene 4-monooxygenase was determined by X-ray crystallography in the 2Fe-2S state at a resolution of 1.48 A using single-wavelength anomalous dispersion phasing with the [2Fe-2S] center. The structure consists of ten beta-strands arranged into the three antiparallel beta-sheet topology observed in all Rieske proteins. Trp69 of T4moC is adjacent to the [2Fe-2S] centre, which displaces a loop containing the conserved Pro81 by approximately 8 A away from the [2Fe-2S] cluster compared with the Pro loop in the closest structural and functional homolog, the Rieske-type ferredoxin BphF from biphenyl dioxygenase. In addition, T4moC contains five hydrogen bonds to the [2Fe-2S] cluster compared with three hydrogen bonds in BphF. Moreover, the electrostatic surface of T4moC is distinct from that of BphF. These structural differences are identified as possible contributors to the evolutionary specialization of soluble Rieske-type ferredoxins between the diiron monooxygenases and cis-dihydrodiol-forming dioxygenases.
利用与[2Fe-2S]中心的单波长反常色散相位法，通过X射线晶体学在分辨率为1.48 Å的2Fe-2S状态下测定了甲苯4-单加氧酶的Rieske型铁氧化还原蛋白（T4moC）的结构。该结构由十条β链组成，排列成在所有Rieske蛋白中都观察到的三个反平行β折叠拓扑结构。T4moC的Trp69与[2Fe-2S]中心相邻，与最接近的结构和功能同源物——联苯双加氧酶的Rieske型铁氧化还原蛋白BphF中的Pro环相比，它使包含保守Pro81的环从[2Fe-2S]簇移开了约8 Å。此外，与BphF中的三个氢键相比，T4moC与[2Fe-2S]簇有五个氢键。而且，T4moC的静电表面与BphF的不同。这些结构差异被认为可能是导致二铁单加氧酶和顺式二氢二醇形成双加氧酶之间可溶性Rieske型铁氧化还原蛋白进化特化的原因。
