Wang Hui, Li Hongyan, Cai Bin, Huang Zhong-Xian, Sun Hongzhe
Department of Chemistry and Open Laboratory of Chemical Biology, The University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China.
J Biol Inorg Chem. 2008 Mar;13(3):411-9. doi: 10.1007/s00775-007-0331-x. Epub 2007 Dec 22.
Metallothionein-3 (MT-3), or neuronal growth inhibitory factor, which exhibits growth inhibitory activity, is a brain-specific metallothionein. In this study, the effect of nitric oxide (NO) on metal release (using Cd2+ as a probe) from MT-3 was examined by 113Cd and 2D [1H-15N] heteronuclear single-quantum coherence NMR spectroscopy. The exposure of human MT-3 to NO leads to a nonselective release of the three metals from the beta-domain. In contrast to metallothionein-1 and metallothionein-2, two of the bound metals in the alpha-domain were also partially released, with the domain structure remaining almost unchanged. Further addition of NO resulted in the complete release of metals and concomitant unfolding of the protein. The preference of release of the two metals in the alpha-domain was attributed to the presence of two slightly different coordination environments for the four cadmium/zinc atoms.
金属硫蛋白-3（MT-3），即神经元生长抑制因子，具有生长抑制活性，是一种脑特异性金属硫蛋白。在本研究中，通过113Cd和二维[1H-15N]异核单量子相干核磁共振光谱法研究了一氧化氮（NO）对MT-3中金属释放（以Cd2+作为探针）的影响。将人MT-3暴露于NO会导致三种金属从β结构域非选择性释放。与金属硫蛋白-1和金属硫蛋白-2不同，α结构域中的两种结合金属也会部分释放，而结构域结构几乎保持不变。进一步添加NO会导致金属完全释放并伴随蛋白质解折叠。α结构域中两种金属释放的偏好归因于四个镉/锌原子存在两种略有不同的配位环境。
