title: Optical control of calcium affinity in a spiroamido-rhodamine based calcium chelator.
abstract: An optically controlled Ca(2+)-chelator 1 was developed to mimic natural calcium oscillations. Compound 1, a spiroamido-rhodamine derivative of 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), underwent cycles of reversible transitions between a colorless closed state and a fluorescent open form. The closed-state exhibited a high affinity for Ca(2+) (K(d): 509 nM) with excellent selectivity over Mg(2+) (K(d): 19 mM). The open isomer had a 350-fold lower Ca(2+) affinity (K(d): 181 μM), while the Mg(2+) affinity was not significantly affected (K(d): 14 mM).
authors.affiliation: Department of Bioengineering, University of California-Berkeley, Berkeley, California 94720, USA.
authors.forename: Liangxing
authors.initials: L
authors.lastname: Wu
authors.forename: Yingrui
authors.initials: Y
authors.lastname: Dai
authors.forename: Gerard
authors.initials: G
authors.lastname: Marriott
mesh_terms: D000577:Amides / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D015394:Molecular Structure; D012235:Rhodamines / Q000737:chemistry*; D013141:Spiro Compounds / Q000737:chemistry*
chemical_list: D000577:Amides; D002614:Chelating Agents; D012235:Rhodamines; D013141:Spiro Compounds; D002118:Calcium