Tuning caged calcium: Photolabile analogues of EGTA with improved optical and chelation properties
Tuning caged calcium: Photolabile analogues of EGTA with improved optical and chelation properties
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DOI：
10.1016/j.ceca.2005.10.003
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发表时间：
2006-01-01
期刊：
影响因子：
4
通讯作者：
Barsotti, RJ
中科院分区：
文献类型：
--
作者：
Ellis-Davies, GCR;Barsotti, RJ
介绍了几种Ca2+选择性光稳定性螯合剂的理化性质。这些分子已被开发作为努力的一部分，以生产笼Ca2+，提高Ca2+螯合性能和光吸收能力的硝基苯- egta （NP-EGTA）。EGTA的四种二甲氧基邻硝基衍生物（称为DMNPE-1至-4）和EGTA的一种类似物（DMNPE-5）已被表征，每一种都在辐照后被一分为二。其中一个笼比NP-EGTA具有更高的亲和力：DMNPE-4对Ca2+的K-d在pH 7.2时为48 nm （pH 7.4时为19 nm）。此外，该笼在350 nm处具有5120 M-1 cm（-1）的大消光系数（NP-EGTA为975 M-1 cm(-1)）。DMNPE-4的其他理化性质有：光解量子产率为0.09；双相Ca2+释放动力学（70%以约48,000 s（-1）的速率释放，30%以1.5 s（-1）的速率释放）和光产物以非常低的亲和力结合Ca2+ (K-d在2 mM范围内，pH 7.2)，因此大多数结合的Ca2+在光解时被快速有效地释放。因此，DMNPE-4具有独特的特性组合，使其成为非常有效的Ca2+笼。(c) 2005 Elsevier Ltd版权所有。
The physico-chemical properties of several Ca2+-selective, photolabile chelators are described. These molecules have been developed as part of an effort to produce a caged Ca2+ that improved upon the Ca2+ chelation properties and light absorption capability of nitrophenyl-EGTA (NP-EGTA). Four dimethoxy-ortho-nitrophenyl derivatives of EGTA (called DMNPE-1 through -4), and one analogue of EGTA (DMNPE-5) have been characterized, each of which is bisected upon irradiation. One of these cages has a higher affinity than NP-EGTA: DMNPE-4 has a K-d for Ca2+ of 48 nm at pH 7.2 (19 nM at pH 7.4). Furthermore, this cage has a large extinction coefficient of 5120 M-1 cm(-1) at 350 nm (cf. 975 M-1 cm(-1) for NP-EGTA). The other physico-chemical properties of DMNPE-4 are: quantum yield of photolysis of 0.09; bipasic Ca2+ release kinetics (70% released with a rate of about 48,000 s(-1) and 30% at 1.5 s(-1)) and photoproducts that bind Ca2+ with very low affinity (K-d in the range of 2 mM, pH 7.2), hence most of the bound Ca2+, is released rapidly and efficiently upon photolysis. Thus, DMNPE-4 has a unique combination of properties that make it an extremely effective Ca2+ cage. (c) 2005 Elsevier Ltd. All rights reserved.