title: The evolution of photosystem I in light of phage-encoded reaction centres.
abstract: Recent structural determinations and metagenomic studies shed light on the evolution of photosystem I (PSI) from the homodimeric reaction centre of primitive bacteria to plant PSI at the top of the evolutionary development. The evolutionary scenario of over 3.5 billion years reveals an increase in the complexity of PSI. This phenomenon of ever-increasing complexity is common to all evolutionary processes that in their advanced stages are highly dependent on fine-tuning of regulatory processes. On the other hand, the recently discovered virus-encoded PSI complexes contain a minimal number of subunits. This may reflect the unique selection scenarios associated with viral replication. It may be beneficial for future engineering of productive processes to utilize 'primitive' complexes that disregard the cellular regulatory processes and to avoid those regulatory constraints when our goal is to divert the process from its original route. In this article, we discuss the evolutionary forces that act on viral reaction centres and the role of the virus-carried photosynthetic genes in the evolution of photosynthesis.
authors.affiliation: Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Mazor
authors.forename: Ilanit
authors.initials: I
authors.lastname: Greenberg
authors.forename: Hila
authors.initials: H
authors.lastname: Toporik
authors.forename: Oded
authors.initials: O
authors.lastname: Beja
authors.forename: Nathan
authors.initials: N
authors.lastname: Nelson
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D005814:Genes, Viral; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D048929:Prochlorococcus / Q000235:genetics / Q000378:metabolism / Q000821:virology; D046940:Synechococcus / Q000235:genetics / Q000378:metabolism / Q000821:virology; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D045331:Photosystem I Protein Complex; D014764:Viral Proteins; D010100:Oxygen