NEW CALCIUM INDICATORS AND BUFFERS WITH HIGH SELECTIVITY AGAINST MAGNESIUM AND PROTONS - DESIGN, SYNTHESIS, AND PROPERTIES OF PROTOTYPE STRUCTURES
NEW CALCIUM INDICATORS AND BUFFERS WITH HIGH SELECTIVITY AGAINST MAGNESIUM AND PROTONS - DESIGN, SYNTHESIS, AND PROPERTIES OF PROTOTYPE STRUCTURES
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DOI：
10.1021/bi00552a018
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发表时间：
1980-01-01
期刊：
影响因子：
2.9
通讯作者：
TSIEN, RY
中科院分区：
文献类型：
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作者：
TSIEN, RY
合理设计和合成了一系列新型的高亲和力缓冲溶液和钙离子光学指示剂。母体化合物是1，2-二(邻氨基苯氧基)乙烷-N，N，N‘’，N‘’-四乙酸(BAPTA)，它是螯合剂EGTA[乙二醇双(β-氨基乙醚)-N，N，N‘，N’‘-四乙酸]的亲属，其中O2和N之间的亚甲基连接被苯环取代。BAPTA及其衍生物对Ca~(2+)的选择性高于EGTA对Mg~(2+)的选择性，但受pH变化的影响要小得多，而且吸收和释放钙的速度更快。母体化合物对钙离子的亲和力(Kd1.1倍)。10~(-7)M在0.1M KCl中)可通过芳环上的电子释放或引出取代基被增强或减弱。通过用杂环N原子取代醚氧，可以进一步改变Ca~(2+)和Mg~(2+)的亲和力。所描述的化合物是吸收在紫外区的荧光钙离子指示剂；在结合钙离子上观察到的非常大的光谱位移符合络合应该阻碍N个孤对电子与芳香环的共轭的预测。含喹啉核衍生物的荧光量子产率对Ca~(2+)的结合具有很高的敏感性，而对Mg~(2+)的结合不敏感。初步的生物学测试显示，细胞内微量注射后，很少或根本没有与膜的结合或毒性效应。
A new family of high-affinity buffers and optical indicators for Ca2+ is rationally designed and synthesized. The parent compound is 1,2-bis(o-aminophenoxy)ethane-N,N,N'',N''-tetraacetic acid (BAPTA), a relative of the chelator EGTA [ethylene glycol bis(.beta.-aminoethyl ether)-N,N,N'',N''-tetraacetic acid] in which methylene links between O2 and N are replaced by benzene rings. BAPTA and its derivatives share the high (> 105) selectivity for Ca2+ over Mg2+ of EGTA, but are very much less affected by pH changes and are faster at taking up and releasing Ca2+. The affinity of the parent compound for Ca2+ (Kd 1.1 .times. 10-7 M in 0.1 M KCl) may be strengthened or weakened by electron-releasing or -withdrawing substitutents on the aromatic rings. The Ca2+ and Mg2+ affinities may further be altered by replacing the ether oxygens by heterocyclic N atoms. The compounds described are fluorescent Ca2+ indicators absorbing in the UV region; the very large spectral shifts observed on binding Ca2+ fit the prediction that complexation should hinder the conjugation of the N lone-pair electrons with the aromatic rings. Derivatives with quinoline nuclei are notable for their high sensitivity of fluorescent quantum yield to the binding of Ca2+ but not of Mg2+. Preliminary biological tests have revealed little or no binding to membranes or toxic effects following intracellular microinjection.