Coudevylle Nicolas, Thureau Aurélien, Hemmerlin Christine, Gelhaye Eric, Jacquot Jean-Pierre, Cung Manh-Thong
Laboratoire de Chimie-Physique Macromoléculaire, UMR 7568 CNRS-INPL, Groupe ENSIC, 1 rue Grandville, B.P. 451, 54001 Nancy Cedex, France.
Biochemistry. 2005 Feb 15;44(6):2001-8. doi: 10.1021/bi047816n.
Assignment of heteronuclear and homonuclear multidimensional NMR spectra permits determination of the first three-dimensional solution structure of a higher-plant thioredoxin h. The collection of 1906 distance restraints, 137 TALOS-derived dihedral restraints, and 66 hydrogen bonds was used in the restrained molecular dynamics protocol to calculate the structure of the reduced form of thioredoxin h1 from poplar with an atomic rmsd of 0.60 +/- 0.12 A. This enzyme exhibits an unusual active site with the sequence WCPPC and original properties in terms of stability and specificity. Compared to other known thioredoxin structures, thioredoxin h1 from poplar adopts the classical "Trx fold". Its atypical active site possesses a conformation similar to that of other common thioredoxins but appears to be more rigid. Moreover, the hydrogen bond network, stabilizing the in-core beta-sheet, is tighter than in Chlamydomonas reinhardtii, explaining the difference in thermostability.
异核和同核多维核磁共振谱的归属使得能够确定高等植物硫氧还蛋白h的首个三维溶液结构。在受限分子动力学协议中，使用了1906个距离约束、137个TALOS衍生的二面角约束和66个氢键来计算杨树硫氧还蛋白h1还原形式的结构，其原子均方根偏差为0.60±0.12埃。这种酶具有一个不寻常的活性位点，序列为WCPPC，在稳定性和特异性方面具有独特性质。与其他已知的硫氧还蛋白结构相比，杨树硫氧还蛋白h1采用经典的“Trx折叠”。其非典型活性位点具有与其他常见硫氧还蛋白相似的构象，但似乎更刚性。此外，稳定核心β-折叠的氢键网络比莱茵衣藻中的更紧密，这解释了热稳定性的差异。
