Novel analogs of cyclic-ADP-ribose: 9-Cyclic etheno-ADP-ribose and cyclic etheno-CDP-ribose

Two novel analogs of cyclic ADP-ribose (cADPR), 9-cyclic etheno-ADP-ribose (1) and cyclic etheno-CDP-ribose (2) were synthesized. We have shown for the first time that enzymatic and biomimetic methods may proceed by different reaction pathways. 1,N6-Etheno-nicotinamide-adenine dinucleotide (3) was converted into 1 using the biomimetic procedure, whereas ADP-ribosyl cyclase transformed 3 into 4. The unique fluorescence property and the strong Ca2+ mobilizing activity of 1 provide investigators with a useful probe for the study of cADPR-binding proteins.