Zweier J L
J Biol Chem. 1983 Nov 25;258(22):13759-60.
The distance between the two metal binding sites of human serum transferrin is calculated from measurements made of the paramagnetic broadening of the EPR spectrum of Cu2+ bound at the NH2-terminal (B) site from Fe3+ bound at the COOH-terminal (A) site. Complexes of monoferric(A)-monocupric(B) transferrin, monocupric(B) transferrin, and monogallium(A)-monocupric(B) transferrin were prepared under identical conditions. Computer simulation and direct measurement of the EPR spectra from these complexes demonstrate a paramagnetic broadening of 0.6 +/- 0.1 G in the line width of the Cu2+ spectrum due to the paramagnetic Fe3+ bound at the other site. The distance between the two metal binding sites is calculated to be 41.6 +/- 2.8 A.
人血清转铁蛋白两个金属结合位点之间的距离，是通过对结合于氨基末端（B）位点的Cu2+的电子顺磁共振（EPR）谱线的顺磁展宽进行测量而计算得出的，该顺磁展宽由结合于羧基末端（A）位点的Fe3+引起。在相同条件下制备了单铁（A）-单铜（B）转铁蛋白、单铜（B）转铁蛋白和单镓（A）-单铜（B）转铁蛋白复合物。对这些复合物的EPR谱进行计算机模拟和直接测量表明，由于另一位点结合的顺磁Fe3+，Cu2+谱线宽度出现了0.6±0.1 G的顺磁展宽。计算得出两个金属结合位点之间的距离为41.6±2.8 Å。
