Photosystem I gene cassettes are present in marine virus genomes.
Cyanobacteria of the Synechococcus and Prochlorococcus genera are important contributors to photosynthetic productivity in the open oceans. Recently, core photosystem II (PSII) genes were identified in cyanophages and proposed to function in photosynthesis and in increasing viral fitness by supplementing the host production of these proteins. Here we show evidence for the presence of photosystem I (PSI) genes in the genomes of viruses that infect these marine cyanobacteria, using pre-existing metagenomic data from the global ocean sampling expedition as well as from viral biomes. The seven cyanobacterial core PSI genes identified in this study, psaA, B, C, D, E, K and a unique J and F fusion, form a cluster in cyanophage genomes, suggestive of selection for a distinct function in the virus life cycle. The existence of this PSI cluster was confirmed with overlapping and long polymerase chain reaction on environmental DNA from the Northern Line Islands. Potentially, the seven proteins encoded by the viral genes are sufficient to form an intact monomeric PSI complex. Projection of viral predicted peptides on the cyanobacterial PSI crystal structure suggested that the viral-PSI components might provide a unique way of funnelling reducing power from respiratory and other electron transfer chains to the PSI.
Sharon
Itai
I
Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.|Faculty of Computer Science, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Alperovitch
Ariella
A
Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Rohwer
Forest
F
Department of Biology, San Diego State University, San Diego 92182, California, USA.|Center for Microbial Sciences, San Diego State University, San Diego 92182, California, USA.
Haynes
Matthew
M
Department of Biology, San Diego State University, San Diego 92182, California, USA.
Glaser
Fabian
F
Bioinformatics Knowledge Unit, Lorry I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Atamna-Ismaeel
Nof
N
Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Pinter
Ron Y
RY
Faculty of Computer Science, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Partensky
Frédéric
F
CNRS and UPMC-Université Paris 6 (UMR 7144), Station Biologique, 29682 Roscoff, France.
Koonin
Eugene V
EV
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
Wolf
Yuri I
YI
National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
Nelson
Nathan
N
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Daniella Rich Institute for Structural Biology, Tel Aviv University, Tel Aviv 69978, Israel.
Béjà
Oded
O
Faculty of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics* / Q000378:metabolism; D044822:Biodiversity; D005798:Genes, Bacterial / Q000235:genetics; D005814:Genes, Viral / Q000235:genetics*; D016680:Genome, Bacterial / Q000235:genetics; D016679:Genome, Viral / Q000235:genetics*; D005843:Geography; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D016366:Open Reading Frames / Q000235:genetics; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000235:genetics; D045331:Photosystem I Protein Complex / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D048929:Prochlorococcus / Q000821:virology*; D011487:Protein Conformation; D012623:Seawater / Q000382:microbiology*; D046940:Synechococcus / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014871:Water Microbiology
D018829:Adhesins, Bacterial; D008074:Lipoproteins; D045331:Photosystem I Protein Complex; C085000:PsaA protein, Streptococcus; D014764:Viral Proteins