Vanin A F, Serezhenkov V A, Mikoyan V D, Genkin M V
Institute of Chemical Physics, Russian Academy of Sciences, Moscow.
Nitric Oxide. 1998;2(4):224-34. doi: 10.1006/niox.1998.0180.
The parameters of EPR signal from dinitrosyl-iron complexes (DNIC) with bovine serum albumin (BSA), horse hemoglobin (Hb), and apometallothionein (apo-Mt) of horse kidney incorporating one (BSA, Hb) or two thiol-containing ligands (apo-Mt) were compared. The EPR signal from DNIC-BSA was characterized by the rhombic symmetry of g tensor at room temperature of signal recording (ambient temperature) or at 77K in the solution frozen in the presence of glycerol. In freezing of the solution in the absence of glycerin, under the exposure of DNIC-BSA to negatively charged sodium dodecyl sulfate (SDS) ions, or in the incorporation of DNIC-BSA into the reversed micelles formed by negatively charged ions of surfactant aerosol OT, the symmetry of the g tensor of DNIC-BSA EPR signal increased to axial. A similarly high symmetry of g tensor was observed for the DNIC-Hb EPR signal in the absence of any influence on this protein complex. The shape of EPR signals from these preparations recorded at 77K was identical to that of EPR signal from DNIC with cysteine in frozen solution. In this connection it was concluded that the EPR signal from this low-molecular DNIC with the (RS-)2Fe+(NO+)2 structure cannot be considered as a peculiar "fingerprint" of DNIC with the same structure in biosystems. In such systems the same signal can originate from protein DNIC incorporating only one thiol-containing ligand along with a nonthiol ligand. The EPR signal displayed by DNIC with apo-Mt with a high content of cysteine residues at room temperature of registration was identical to the EPR signal from frozen solution of DNIC with cysteine. This protein DNIC is apparently characterized by the same structure as DNIC with cysteine.
比较了二亚硝基铁配合物（DNIC）与牛血清白蛋白（BSA）、马血红蛋白（Hb）以及马肾脱金属硫蛋白（apo-Mt）结合一个（BSA、Hb）或两个含硫醇配体（apo-Mt）时的电子顺磁共振（EPR）信号参数。DNIC-BSA的EPR信号在信号记录的室温（环境温度）或在甘油存在下冷冻的溶液于77K时，以g张量的菱形对称性为特征。在无甘油的溶液冷冻过程中、DNIC-BSA暴露于带负电荷的十二烷基硫酸钠（SDS）离子时，或在将DNIC-BSA掺入由带负电荷的表面活性剂气溶胶OT离子形成的反胶束中时，DNIC-BSA的EPR信号g张量的对称性增加到轴向。在对该蛋白质复合物无任何影响的情况下，DNIC-Hb的EPR信号也观察到类似的高g张量对称性。在77K记录的这些制剂的EPR信号形状与冷冻溶液中含半胱氨酸的DNIC的EPR信号形状相同。由此得出结论，这种具有（RS-）2Fe+（NO+）2结构的低分子DNIC的EPR信号不能被视为生物系统中具有相同结构的DNIC的特殊“指纹”。在这样的系统中，相同的信号可能来自仅结合一个含硫醇配体和一个非硫醇配体的蛋白质DNIC。在记录的室温下，含高含量半胱氨酸残基的apo-Mt的DNIC显示的EPR信号与含半胱氨酸的DNIC冷冻溶液的EPR信号相同。这种蛋白质DNIC显然具有与含半胱氨酸的DNIC相同的结构特征。
