Department of Physics, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.
J Inorg Biochem. 2011 Sep;105(9):1131-7. doi: 10.1016/j.jinorgbio.2011.05.020. Epub 2011 Jun 12.
The function of neuroglobin, a member of the vertebrate globin family, is still unknown. In human neuroglobin (NGB), the formation of a disulfide bridge between the CysCD7 and CysD5 is known to affect the heme environment and its ligand-binding kinetics. Here, we show by means of EPR that the PheB10 residue plays a key role in transmitting the structural information from the disulfide bridge to the heme-pocket region. While formation of a disulfide bridge in ferric wild-type NGB leads to a considerable change of its EPR parameters, only minor changes are observed in the case of ferric PheB10Leu NGB. Furthermore, wild-type NGB is found to be much more stable in the presence of H(2)O(2) than its PheB10Leu or its HisE7Leu mutants. While tyrosyl radicals are induced in HisE7Leu NGB by the addition of H(2)O(2), this is not the case for wild-type and PheB10Leu NGB. The results will be discussed in terms of the protein's putative functions.
神经球蛋白的功能仍然未知，它是脊椎动物球蛋白家族的一员。在人类神经球蛋白（NGB）中，CysCD7 和 CysD5 之间形成二硫键已知会影响血红素环境及其配体结合动力学。在这里，我们通过 EPR 表明 PheB10 残基在将结构信息从二硫键传递到血红素口袋区域方面起着关键作用。虽然在三价野生型 NGB 中二硫键的形成导致其 EPR 参数发生相当大的变化，但在三价 PheB10Leu NGB 的情况下仅观察到较小的变化。此外，与 PheB10Leu 或 HisE7Leu 突变体相比，在存在 H2O2 的情况下野生型 NGB 被发现更加稳定。虽然在添加 H2O2 后 HisE7Leu NGB 中诱导了酪氨酸自由基，但在野生型和 PheB10Leu NGB 中则不是这样。结果将根据该蛋白质的假定功能进行讨论。
