Fluorescent metal ion indicators based on benzoannelated crown systems: a green fluorescent indicator for intracellular sodium ions.

The synthesis and metal binding properties of cation-sensitive fluorescent indicators intended for biological applications are described. The increase of the crown ether ring size enhances the affinity for larger cations, but weakens the fluorescent response and selectivity. A compound having a 15-crown-5 chelator directly attached to a 2,7-difluoroxanthenone fluorophore loads into live cells and responds to sodium ion concentration changes with large fluorescence increases in the visible wavelength range.

Novel fluo-4 analogs for fluorescent calcium measurements.

We report new fluorescent calcium indicators based on fluo-4. Attachment of a carboxamide or methylenecarboxamide moiety to the BAPTA chelator portion of fluo-4 allowed for the attachment of dextrans, protein-reactive moieties, and biotin. In particular, a high affinity fluo-4 dextran conjugate was prepared and shown to be functional in brain slices.

Fluorescent sodium ion indicators based on the 1,7-diaza-15-crown-5 system.

A series of novel sodium ion-sensitive fluorescent reagents suitable for biological applications is described. The chelator nitrogen atom substituents affect the selectivity and affinity of cation binding, while the nature of the fluorophore determines the type of fluorescent response to metal ion chelation.

Quantitative comparison of long-wavelength Alexa Fluor dyes to Cy dyes: fluorescence of the dyes and their bioconjugates.

Amine-reactive N-hydroxysuccinimidyl esters of Alexa Fluor fluorescent dyes with principal absorption maxima at about 555 nm, 633 nm, 647 nm, 660 nm, 680 nm, 700 nm, and 750 nm were conjugated to antibodies and other selected proteins. These conjugates were compared with spectrally similar protein conjugates of the Cy3, Cy5, Cy5.5, Cy7, DY-630, DY-635, DY-680, and Atto 565 dyes.

A new mitochondrial fluorescent zinc sensor.

A novel cationic fluorescent zinc (Zn2+) indicator (RhodZin-3) with nanomolar affinity for Zn2+ has been synthesized. RhodZin-3 exhibits large pH-independent fluorescence increases in the orange region of the visible wavelength spectrum with increasing zinc concentrations, and no sensitivity to physiologically relevant Ca2+ concentrations. Experiments in neuronal cell cultures show that RhodZin-3 effectively localizes into mitochondria and detects changes of intramitochondrial free Zn2+ ([Zn2+]m).

Ykt6p is a multifunctional yeast R-SNARE that is required for multiple membrane transport pathways to the vacuole.

Intracellular membrane fusion requires that membrane-bound soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins on both vesicle and target membranes form a highly specific complex necessary to bring the membranes close in space. Ykt6p is a yeast R-SNARE protein that has been implicated in retrograde transport to the cis-Golgi compartment. Ykt6p has been also been found to fractionate with vacuole membranes and participate in a vacuolar SNARE complex in homotypic vacuole fusion.

New Ca2+ fluoroionophores based on the BODIPY fluorophore.

Calcium (Ca(2+)) fluoroionophores are useful in cell-based functional assays of G-protein coupled receptor (GPCR) activation or ion channel modulation. In this paper we describe new calcium probes that improve or overcome certain deficiencies in existing probes. These new fluoroionophores are based on acylation of amino-BAPTA [BAPTA = glycine, N,N'-(1,2-ethanediyl-bis(oxy-2,1-phenylene)) bis(N-(carboxymethyl))] with fluorescent BODIPY(R) propionates [BODIPY = 4,4-difluoro-5,7-dimethyl- 4-bora-3a,4a-diaza-s-indacene].