ADPRIBOSYLATION REACTION BY FREE ADPRIBOSE IN SULFOLOBUS-SOLFATARICUS, A THERMOPHILIC ARCHAEON

In the archaeon Sulfolobus solfataricus, protein ADPribosylation by fr ee ADPribose was demonstrated by testing both [adenine-C-14(U)]ADPR an d [adenine-C-14(U)]NAD as substrates. The occurrence of this process w as shown by using specific experimental conditions. Increasing the inc ubation time and lowering the pH of the reaction mixture enhanced the protein glycation by free ADPribose. At pH 7.5 and 10 min incubation, the incorporation of free ADPribose into proteins was highly reduced. Under these conditions, the autoradiographic pattern showed that, amon g the targets of ADPribose electrophoresed after incubation with P-32- NAD, the proteins modified by free P-32-ADPribose mostly corresponded to high molecular mass components. Among the compounds known to inhibi t the eukaryotic poly-ADPribose polymerase, only ZnCl2 highly reduced the ADPribose incorporation from NAD into the ammonium sulphate precip itate. A 20% inhibition was measured in the presence of nicotinamide o r 3-aminobenzamide. No inhibition was observed replacing NAD with ADPR as substrate. (C) 1997 Wiley-Liss, Inc.