TY - JOUR A1 - Ducrot, Aurélien A1 - Tron, Arnaud A1 - Bofinger, Robin A1 - Sanz Beguer, Ingrid A1 - Pozzo, Jean-Luc A1 - McClenaghan, Nathan D. T1 - Photoreversible stretching of a BAPTA chelator marshalling Ca2+-binding in aqueous media JF - Beilstein Journal of Organic Chemistry PY - 2019/// VL - 15 SP - 2801 EP - 2811 SN - 1860-5397 DO - 10.3762/bjoc.15.273 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.15.273 KW - azobenzene KW - BAPTA KW - calcium binding KW - photorelease KW - photoswitch N2 - 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. ER -