Kropf A J, Bunker B A, Eisner M, Moss S C, Zecca L, Stroppolo A, Crippa P R
Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 USA.
Biophys J. 1998 Dec;75(6):3135-42. doi: 10.1016/S0006-3495(98)77755-0.
X-ray absorption fine-structure spectroscopy is used to study the local environment of the iron site in natural (human) neuromelanin extracted from substantia nigra tissue and in various synthetic neuromelanins. All the materials show Fe centered in a nearest neighbor sixfold (distorted) oxygen octahedron; the Fe-O distances, while slightly different in the natural and synthetic neuromelanin, are both approximately 2.0 A. Appreciable differences arise, however, in the second (and higher) coordination shells. In this case the synthetic melanin has the four planar oxygens bound to carbon rings with Fe-C distances of approximately 2.82 and 4.13 A; the human sample does not show the 2.82 A link but instead indicates a double shell at approximately 3.45 and 3.78 A.
X射线吸收精细结构光谱法用于研究从黑质组织中提取的天然（人类）神经黑色素以及各种合成神经黑色素中铁位点的局部环境。所有材料均显示铁以最近邻六重（扭曲）氧八面体为中心；铁-氧距离在天然和合成神经黑色素中略有不同，但均约为2.0埃。然而，在第二（及更高）配位层中出现了明显差异。在这种情况下，合成黑色素有四个平面氧与碳环相连，铁-碳距离约为2.82和4.13埃；人类样本没有显示出2.82埃的键，而是在约3.45和3.78埃处显示出一个双层结构。
