title: Viruses infecting marine picoplancton encode functional potassium ion channels.
abstract: Phycodnaviruses are dsDNA viruses, which infect algae. Their large genomes encode many gene products, like small K(+) channels, with homologs in prokaryotes and eukaryotes. Screening for K(+) channels revealed their abundance in viruses from fresh-water habitats. Recent sequencing of viruses from marine algae or from salt water in Antarctica revealed sequences with the predicted characteristics of K(+) channels but with some unexpected features. Two genes encode either 78 or 79 amino acid proteins, which are the smallest known K(+) channels. Also of interest is an unusual sequence in the canonical α-helixes in K(+) channels. Structural prediction algorithms indicate that the new channels have the conserved α-helix folds but the algorithms failed to identify the expected transmembrane domains flanking the K(+) channel pores. In spite of these unexpected properties electophysiological studies confirmed that the new proteins are functional K(+) channels.
authors.affiliation: Membrane Biophysics Group, Dept. of Biology, Technical University Darmstadt, Germany.
authors.forename: Fenja
authors.initials: F
authors.lastname: Siotto
authors.affiliation: Membrane Biophysics Group, Dept. of Biology, Technical University Darmstadt, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Martin
authors.affiliation: Membrane Biophysics Group, Dept. of Biology, Technical University Darmstadt, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Rauh
authors.affiliation: Department of Plant Pathology and Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA.
authors.forename: James L
authors.initials: JL
authors.lastname: Van Etten
authors.affiliation: Membrane Biophysics Group, Dept. of Biology, Technical University Darmstadt, Germany.
authors.forename: Indra
authors.initials: I
authors.lastname: Schroeder
authors.affiliation: Dipartimento di Biologia Università degli Studi di Milano e Istituto di Biofisica, CNR, Milano, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Moroni
authors.affiliation: Membrane Biophysics Group, Dept. of Biology, Technical University Darmstadt, Germany. Electronic address: thiel@bio.tu-darmstadt.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Thiel
mesh_terms: D000595:Amino Acid Sequence; D002708:Chlorella / Q000821:virology*; D055724:Electrophysiological Phenomena; D019143:Evolution, Molecular; D057809:HEK293 Cells; D006801:Humans; D017862:Phycodnaviridae / Q000235:genetics* / Q000502:physiology; D010802:Phylogeny; D015221:Potassium Channels / Q000235:genetics* / Q000378:metabolism; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D015221:Potassium Channels; D014764:Viral Proteins
keywords: Algal viruses; Chlorella viruses; K(+) channel evolution; Kcv; Virus evolution