IDENTIFICATION OF THE REACTION-PRODUCTS OF (2'-5')OLIGOADENYLATE SYNTHETASE IN THE MARINE SPONGE

Previously we reported on the presence of a high (2'-5')oligoadenylate synthetase activity in the marine sponge Geodia cydonium [Kuusksalu, A., Pihlak, A., Muller, W. E. G. & Kelve. M. (1995) Eur. J. Biochem. 2 32, 351-357]. The presence of (2'-5')oligoadenylates [(2'-5')A] in cru de sponge extract was shown by radioimmunoassay and by their HPLC comi gration with authentic (2'-5')A oligomers. Tn addition, the sponge (2' -5')oligoadenylates displayed biological activity, as determined by in hibition studies of protein biosynthesis in rabbit reticulocyte lysate . In the present study individual (2'-5')oligoadenylates synthesized b y sponge enzyme were separated by HPLC. The exact composition of every oligonucleotide peak eluted was determined by matrix-assisted laser-d esorption-ionization mass spectrometry (MALDI-MS) analysis. The 2'-5' phosphodiester bond in oligoadenylates was verified by NMR analysis. B ased on the high concentration of (2'-5')A oligomers in G. cydonium an d their similarity with those found in mammals we propose that the (2' -5')A system is involved in a cytokine-mediated pathway and/or in a pr otection system against viruses, present in the marine environment.