Free calcium ion concentration is known to govern numerous biological processes and indeed calcium acts as an important biological secondary messenger for muscle contraction, neurotransmitter release, ion-channel gating, and exocytosis. As such, the development of molecules with the ability to instantaneously increase or diminish free calcium concentrations potentially allows greater control over certain biological functions. In order to permit remote regulation of Ca²⁺, a selective BAPTA-type synthetic receptor / host was integrated with a photoswitchable azobenzene motif, which upon photoirradiation would enhance (or diminish) the capacity to bind calcium upon acting on the conformation of the adjacent binding site, rendering it a stronger or weaker binder. Photoswitching was studied in pseudo-physiological conditions (pH 7.2, [KCl] = 100 mM) and dissociation constants for azobenzene cis- and trans-isomers have been determined (0.230 μM and 0.102 μM, respectively). Reversible photoliberation/uptake leading to a variation of free calcium concentration in solution was detected using a fluorescent Ca²⁺ chemosensor.

中文翻译：

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BAPTA螯合剂的光可逆拉伸，将其在水介质中编组成Ca2 +结合

众所周知，游离钙离子浓度控制着许多生物过程，而钙实际上是肌肉收缩，神经递质释放，离子通道门控和胞吐作用的重要生物次级信使。这样，具有瞬时增加或减少游离钙浓度的能力的分子的发展潜在地允许对某些生物学功能的更大控制。为了允许远程调节Ca ²⁺，将选择性的BAPTA型合成受体/宿主与可光转换的偶氮苯基序整合在一起，该基团在光辐照后会在作用于相邻结合位点的构象上增强（或减少）结合钙的能力，从而使其成为更强或更弱的结合剂。在伪生理条件下（pH 7.2，[KCl] = 100 mM）研究了光开关，并确定了偶氮苯顺式和反式异构体的解离常数（分别为0.230μM和0.102μM ）。使用荧光Ca ²⁺化学传感器检测到可逆光解/摄取导致溶液中游离钙浓度的变化。