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2¢,5¢-oligoadenylate (2-5A) synthetases are known as components of the interferon-induced cellular defence mechanism in mammals. The existence of 2-5A synthetases in the evolutionarily lowest multicellular animals, the marine sponges, has been demonstrated and the respective candidate genes from Geodia cydoniumandSuberites domunculahave been identified. | ễFEBS Journal Expression and characterization of recombinant 2z 5z-oligoadenylate synthetase from the marine sponge Geodia cydonium Mailis Pari1 Anne Kuusksalu2 Annika Lopp2 Tonu Reintamm2 Just Justesen3 and Merike Kelve1 2 1 Department of Gene Technology Tallinn University of Technology Estonia 2 Department of Molecular Genetics NationalInstitute of ChemicalPhysics and Biophysics Tallinn Estonia 3 Department of Molecular Biology Aarhus University Denmark Keywords Geodia cydonium marine sponge oligoadenylates recombinant 2-5A synthetase RNA binding Correspondence M. Kelve Department of Gene Technology Tallinn University of Technology Akadeemia tee 15 Tallinn 12618 Estonia Fax 372 6204401 Tel 372 6204432 E-mail merike.kelve@ttu.ee Received 20 December 2006 revised 7 May 2007 accepted 11 May 2007 doi 10.1111 j.1742-4658.2007.05878.x 2 5 -oligoadenylate 2-5A synthetases are known as components of the interferon-induced cellular defence mechanism in mammals. The existence of 2-5A synthetases in the evolutionarily lowest multicellular animals the marine sponges has been demonstrated and the respective candidate genes from Geodia cydonium and Suberites domuncula have been identified. In the present study the putative 2-5A synthetase cDNA from G. cydonium was expressed in an Escherichia coli expression system to characterize the enzymatic activity of the recombinant polypeptide. Our studies reveal that unlike the porcine recombinant 2-5A synthetase the sponge recombinant protein associates strongly with RNA from E. coli forming a heterogeneous set of complexes. No complete dissociation of the complex occurs during purification of the recombinant protein and the RNA constituent is partially protected from RNase degradation. We demonstrate that the sponge recombinant 2-5A synthetase in complex with E. coli RNA catalyzes the synthesis of 2 5 -phosphodiester-linked 5 -triphosphorylated oligoadenylates from ATP although with a low specific activity. Poly I -poly C an efficient
