Miki M, Wahl P
Biochim Biophys Acta. 1985 Apr 5;828(2):188-95. doi: 10.1016/0167-4838(85)90056-1.
Fluorescence energy transfers were studied in order to investigate the spatial relationships between the nucleotide-binding site, the metal-binding site and the Cys-373 residue in the G-actin molecule. When 1-N6-ethenoadenosine-5'-triphosphate (epsilon-ATP) in the nucleotide-binding site and Co2+ or Ni2+ in the metal-binding site were used as fluorescence donor and acceptor, respectively, the fluorescence intensity of epsilon-ATP was perfectly quenched by Ni2+ or Co2+. This indicated that the nucleotide-binding site is very close to the metal-binding site; the distance should be less than 10 A. When N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (IAEDANS) bound to Cys-373 residue and Co2+ in the metal-binding site were used as a fluorescence donor and an acceptor, respectively, the transfer efficiency was equal to 5 +/- 1%. The corresponding distance was calculated to be 23-32 A, assuming a random orientation factor K2 = 2/3.
为了研究G-肌动蛋白分子中核苷酸结合位点、金属结合位点和半胱氨酸-373残基之间的空间关系，对荧光能量转移进行了研究。当核苷酸结合位点中的1-N6-乙烯腺苷-5'-三磷酸（ε-ATP）和金属结合位点中的Co2+或Ni2+分别用作荧光供体和受体时，ε-ATP的荧光强度被Ni2+或Co2+完全淬灭。这表明核苷酸结合位点非常靠近金属结合位点；距离应小于10埃。当与半胱氨酸-373残基结合的N-碘乙酰基-N'-(5-磺基-1-萘基)乙二胺（IAEDANS）和金属结合位点中的Co2+分别用作荧光供体和受体时，转移效率等于5±1%。假设随机取向因子K2 = 2/3，计算出相应的距离为23-32埃。
