CYTOCHROME-C INTERACTION WITH YEAST CYTOCHROME-B2 - HEME DISTANCES DETERMINED BY ENERGY-TRANSFER IN FLUORESCENCE RESONANCE
CYTOCHROME-C INTERACTION WITH YEAST CYTOCHROME-B2 - HEME DISTANCES DETERMINED BY ENERGY-TRANSFER IN FLUORESCENCE RESONANCE
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DOI：
10.1111/j.1432-1033.1980.tb04854.x
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
WOODROW, GV
中科院分区：
文献类型：
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作者：
VANDERKOOI, JM;GLATZ, P;WOODROW, GV
用锌或锡等封闭壳金属代替血红素铁制备了细胞色素c的荧光衍生物。细胞色素c的无铁衍生物与酵母乳酸脱氢酶（细胞色素b2）具有化学计量学和高亲和力。卟啉、Zn（II）或Sn（IV）细胞色素c的荧光与细胞色素b的血红素吸收之间存在光谱重叠；正如福斯特的能量传递理论所预测的那样，偶极-偶极相互作用是可能的。细胞色素c衍生物的荧光产率和荧光衰减谱的变化与血红素距离足够接近以进行偶极相互作用的观点一致。从数据计算出的距离取决于能量传递理论中的假设和实验中的不确定性。可以认为，由于金属卟啉的对称性，两个血红素的相对取向不会在计算中引入显著的不确定性。无铁细胞色素的衰减谱是复杂的，可能反映了多肽链在荧光寿命期间的结构重排。稳态荧光产率表明，平均距离约为1.8 nm。
Fluorescent derivatives of cytochrome c were prepared by replacing the heme iron with closed-shell metals such as Zn or tin. The iron-free derivatives of cytochrome c bind to yeast lactate dehydrogenase (cytochrome b2) stoichiometrically and with high affinity. Spectral overlap exists between the fluorescence of porphyrin, Zn(II) or Sn(IV) cytochrome c and the absorption of the heme of cytochrome b; dipole-dipole interaction is possible as predicted by Forster''s theory of energy transfer. Changes in the fluorescence yield and the fluorescent decay profile of the cytochrome c derivatives are consistent with the view that the heme distance is sufficiently close for dipolar interactions. The distance calculated from the data depends on assumptions in the theory for energy transfer and uncertainties in the experiment. It can be argued that due to the symmetry of the metalloporphyrins the relative orientations of the 2 hemes do not introduce a significant uncertainty in the calculation. The decay profiles of the iron-free cytochromes are complex, possibly reflecting structural rearrangement of the polypeptide chain during the fluorescent lifetime. The steady-state fluorescent yields would indicate that the mean distance is around 1.8 nm.