Morrison M Scott, Cobine Paul A, Hegg Eric L
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA.
J Biol Inorg Chem. 2007 Nov;12(8):1129-39. doi: 10.1007/s00775-007-0279-x. Epub 2007 Aug 9.
The crystal structure of Cnx1G, an enzyme involved in the biosynthesis of the molybdenum cofactor (Moco) in Arabidopsis thaliana, revealed the remarkable feature of a copper ion bound to the dithiolene unit of a molybdopterin intermediate (Kuper et al. Nature 430:803-806, 2004). To characterize further the role of copper in Moco biosynthesis, we examined the in vivo and/or in vitro activity of two Moco-dependent enzymes, dimethyl sulfoxide reductase (DMSOR) and nitrate reductase (NR), from cells grown under a variety of copper conditions. We found the activities of DMSOR and NR were not affected when copper was depleted from the media of either Escherichia coli or Rhodobacter sphaeroides. These data suggest that while copper may be utilized during Moco biosynthesis when it is available, copper does not appear to be strictly required for Moco biosynthesis in these two organisms.
Cnx1G是一种参与拟南芥钼辅因子（Moco）生物合成的酶，其晶体结构揭示了一个显著特征：一个铜离子与一种钼蝶呤中间体的二硫烯单元结合（库珀等人，《自然》430:803 - 806，2004年）。为了进一步阐明铜在Moco生物合成中的作用，我们检测了在多种铜条件下生长的细胞中两种依赖Moco的酶——二甲基亚砜还原酶（DMSOR）和硝酸还原酶（NR）的体内和/或体外活性。我们发现，当从大肠杆菌或球形红杆菌的培养基中去除铜时，DMSOR和NR的活性并未受到影响。这些数据表明，虽然在有铜可利用时，铜可能在Moco生物合成过程中被利用，但在这两种生物体中，铜似乎并非Moco生物合成所严格必需的。
