Cheddar G, Tollin G
Department of Biochemistry, University of Arizona, Tucson 85721.
Arch Biochem Biophys. 1990 Apr;278(1):265-8. doi: 10.1016/0003-9861(90)90257-y.
When polylysine is complexed to flavodoxin at low ionic strength, the electrostatic potential of the region which is involved in electron transfer is modified such that positively charged oxidants react more slowly with flavodoxin semiquinone, and negatively charged oxidants react more rapidly. The reaction rate of the uncharged benzoquinone molecule is unaffected. An especially strong effect (approximately 200-fold) occurs with ferricyanide. This is interpreted in terms of electrostatic control of the reaction site. Complexation also changes the conformation of the region around the FMN prosthetic group, which is reflected in the fluorescence and circular dichroism spectra of the protein.
当聚赖氨酸在低离子强度下与黄素氧还蛋白复合时，参与电子转移区域的静电势会发生改变，使得带正电荷的氧化剂与黄素氧还蛋白半醌的反应更慢，而带负电荷的氧化剂反应更快。不带电荷的苯醌分子的反应速率不受影响。铁氰化物会产生特别强烈的效应（约200倍）。这可以从反应位点的静电控制角度来解释。复合作用还会改变FMN辅基周围区域的构象，这在蛋白质的荧光和圆二色光谱中有所体现。
