LaPorte D C, Keller C H, Olwin B B, Storm D R
Biochemistry. 1981 Jul 7;20(14):3965-72. doi: 10.1021/bi00517a004.
Calmodulin was derivatized with 5-[[[(iodoacetyl)amino]ethyl]amino]-1-naphthalenesulfonic acid to fluorescently label the protein. This derivative (AEDANS.CaM) stimulated the Ca2+-sensitive cyclic nucleotide phosphodiesterase and formed Ca2+-dependent complexes with troponin I and the phosphodiesterase. Association between AEDANS.CaM and these proteins was directly monitored by changes in fluorescence anisotropy. The dissociation constants for the AEDANS.CaM--troponin I and AEDANS.CaM--phosphodiesterase complexes were 60 nM and 4 nM, respectively. This fluorescent derivative of calmodulin appears suitable for direct monitoring of the complexes between calmodulin and calmodulin binding proteins. Rotational diffusion of AEDANS.CaM was also measured with fluorescence anisotropy. These measurements indicated that the shape of calmodulin in solution is best approximated by a prolate ellipsoid.
用5-[[[(碘乙酰基)氨基]乙基]氨基]-1-萘磺酸对钙调蛋白进行衍生化，以对该蛋白质进行荧光标记。这种衍生物（AEDANS.CaM）刺激钙敏感的环核苷酸磷酸二酯酶，并与肌钙蛋白I和磷酸二酯酶形成钙依赖性复合物。通过荧光各向异性的变化直接监测AEDANS.CaM与这些蛋白质之间的结合。AEDANS.CaM - 肌钙蛋白I和AEDANS.CaM - 磷酸二酯酶复合物的解离常数分别为60 nM和4 nM。这种钙调蛋白的荧光衍生物似乎适用于直接监测钙调蛋白与钙调蛋白结合蛋白之间的复合物。还通过荧光各向异性测量了AEDANS.CaM的旋转扩散。这些测量表明，溶液中钙调蛋白的形状最接近长椭球体。
