SYNTHESIS OF A HIGHLY LUMINESCENT TERBIUM CHELATE AND ITS APPLICATION TO ACTIN
SYNTHESIS OF A HIGHLY LUMINESCENT TERBIUM CHELATE AND ITS APPLICATION TO ACTIN
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DOI：
10.1016/0167-4838(92)90509-c
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发表时间：
1992-09-25
期刊：
影响因子：
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通讯作者：
MUNEKATA, E
中科院分区：
文献类型：
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作者：
ANDO, T;YAMAMOTO, T;MUNEKATA, E
我们合成了一种高发光的铽螯合物，它由DTPA作为螯合基团，鬼笔苷作为肌动蛋白结合配体和作为Th发射敏化剂的芳香环组成。该合成基于DTPA二酐的性质，其具有与两种胺反应的能力，同时保留其螯合Tb 3+的能力（所得DTPA具有三个羧基）。我们筛选了17种芳香族化合物，它们的能力，敏化Th发射近紫外激发。所有测试的化合物都具有6元环和一个或两个氨基。其中，胞嘧啶是最好的增敏剂。从峰-峰比，Tb-DTPa-胞嘧啶-鬼笔蛋白标记的肌动蛋白的溶液的荧光强度约为四甲基罗丹明的等摩尔溶液的四分之一。激发峰在302 nm左右。用这种新的Th螯合物染色的单个肌纤维的发射是如此强烈，以至于我们可以在短时间内积累足够的光子计数。此外，肌动蛋白束染色的Th螯合物能够在荧光显微镜下可视化。该螯合剂对Tb ~（3+）的稳定常数为10（22.46）M ~（-1）。该值与DTPA非常相似，DTPA具有5个羧基。新的Tb螯合物具有额外的便利性。它是电中性的，这使得它非常适合研究肌动蛋白上铽位点周围的静电环境。我们提供有关这个问题的数据。Tb 3+本身是光学各向同性的。然而，Th螯合物的胞嘧啶具有极化吸收跃迁偶极矩。因此，结合长寿命的激发态，合成的Tb螯合物具有潜在的服务于探测肌动蛋白丝的缓慢旋转松弛。我们可以简单地用其他试剂取代鬼笔蛋白，不仅标记肌动蛋白，还标记各种蛋白质。这种Th螯合物将是一个非常有用的工具，为各种生物学研究。
We synthesized a highly luminescent terbium chelate which consists of DTPA as a chelating group, phalloin as an actin-binding ligand and an aromatic ring as a sensitizer of Th emission. The synthesis was based on the property of DTPA dianhydride that has the capacity to react with two amines, while retaining its ability to chelate Tb3+ (the resulting DTPA possesses three carboxyl groups). We screened 17 kinds of aromatic compounds for their ability to sensitize Th emission with near UV excitation. All of the compounds tested had both a 6-membered ring and one or two amino group(s). Among them, cytosine was the best sensitizer. From the peak-peak ratio, the fluorescence intensity of a solution of Tb-DTPa-cytosine-phalloin-labeled actin was about one-fourth of an equimolar solution of tetramethylrhodamine. The excitation peak was about 302 nm. Emission from a single muscle fiber stained with this new Th chelate was so intense that we could accumulate sufficient photon counts in a short time. Also, actin bundles stained with the Th chelate were able to be visualized under a fluorescence microscope. The stability constant of the chelator was 10(22.46) M-1 for Tb3+. This value was very similar to that of DTPA, which possessed five carboxyl groups. The new Tb chelate had additional expediencies. It was electrically neutral, which made it quite suitable for studying electrostatic circumstances around the terbium site on actin. We present data on this issue. Tb3+ itself is optically isotropic. However, cytosine of the Th chelate has a polarized absorption transition dipole moment. Therefore, in conjunction with the long-lived excited state, the synthesized Tb chelate has potential of serving to probe the slow rotational relaxation of actin filaments. We can simply replace phalloin with other agents to label not only actin but also various proteins. Such Th chelates will be a quite useful tool for a variety of biological studies.