| Autor: |
Kukovetz K; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany., Hertel B; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany., Schvarcz CR; Department of Oceanography, Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, 1950 East-West Road, Honolulu, HI 96822, USA., Saponaro A; Department of Biosciences and CNR IBF-Mi, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milano, Italy., Manthey M; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany., Burk U; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany., Greiner T; University Clinic for Psychiatry and Psychotherapy, Brandenburg Medical School, Immanuel Klinik Rüdersdorf, Seebad 82/83, 15562 Rüdersdorf, Germany., Steward GF; Department of Oceanography, Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, 1950 East-West Road, Honolulu, HI 96822, USA., Van Etten JL; Department of Plant Pathology and Nebraska Center for Virology, University of Nebraska Lincoln, Lincoln, NE 68583-0900, USA., Moroni A; Department of Biosciences and CNR IBF-Mi, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milano, Italy.; Institute of Biophysics, Consiglio Nazionale delle Ricerche, Via Celoria 26, 20133 Milan, Italy., Thiel G; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany., Rauh O; Membrane Biophysics, Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany. |
| Abstrakt: |
Potassium ion (K + ) channels have been observed in diverse viruses that infect eukaryotic marine and freshwater algae. However, experimental evidence for functional K + channels among these alga-infecting viruses has thus far been restricted to members of the family Phycodnaviridae, which are large, double-stranded DNA viruses within the phylum Nucleocytoviricota . Recent sequencing projects revealed that alga-infecting members of Mimiviridae , another family within this phylum, may also contain genes encoding K + channels. Here we examine the structural features and the functional properties of putative K + channels from four cultivated members of Mimiviridae . While all four proteins contain variations of the conserved selectivity filter sequence of K + channels, structural prediction algorithms suggest that only two of them have the required number and position of two transmembrane domains that are present in all K + channels. After in vitro translation and reconstitution of the four proteins in planar lipid bilayers, we confirmed that one of them, a 79 amino acid protein from the virus Tetraselmis virus 1 (TetV-1), forms a functional ion channel with a distinct selectivity for K + over Na + and a sensitivity to Ba 2+ . Thus, virus-encoded K + channels are not limited to Phycodnaviridae but also occur in the members of Mimiviridae . The large sequence diversity among the viral K + channels implies multiple events of lateral gene transfer. |
