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A fresh look at the evolution and diversification of photochemical reaction centers.

Cardona T - Photosyn. Res. (2014)

Bottom Line: In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments.Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria.The primordial phototrophic ancestor must have had both Type I and Type II reaction centers.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, Exhibition Road, London, SW7 2AZ, UK. t.cardona@imperial.ac.uk.

ABSTRACT
In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments. I show, for example, that the protein folds at the C-terminus of the D1 and D2 subunits of Photosystem II, which are essential for the coordination of the water-oxidizing complex, were already in place in the most ancestral Type II reaction center subunit. I then evaluate the evolution of reaction centers in the context of the rise and expansion of the different groups of bacteria based on recent large-scale phylogenetic analyses. I find that the Heliobacteriaceae family of Firmicutes appears to be the earliest branching of the known groups of phototrophic bacteria; however, the origin of photochemical reaction centers and chlorophyll synthesis cannot be placed in this group. Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria. Finally, I argue that the discrepancies among the phylogenies of the reaction center proteins, chlorophyll synthesis enzymes, and the species tree of bacteria are best explained if both types of photochemical reaction centers evolved before the diversification of the known phyla of phototrophic bacteria. The primordial phototrophic ancestor must have had both Type I and Type II reaction centers.

No MeSH data available.


Related in: MedlinePlus

Reaction center architecture and cofactors. a Top view of a Type II reaction center from Blastochloris viridis highlighting the position of the transmembrane helices, PDB ID: 2PRC (Lancaster and Michel 1997). b Top view of Photosystem II from Thermosynechococcus vulcanus where only the transmembrane helices from the reaction center subunits (D1 and D2) and antenna proteins (CP43 and CP47) are highlighted, PDB ID: 3ARC (Umena et al. 2011). c Top view of Photosystem I from Synechococcus elongatus, PDB ID: 1JB0 (Jordan et al. 2001). d Cofactors in the Type II reaction center from B. viridis, the pigments colored in orange are coordinated or held by the M subunit, while those in gray by the L subunit. e Cofactors in Photosystem II, only those held by the D1 (gray) and D2 (orange) proteins are shown. f Cofactors in Photosystem I, those coordinated by the PsaA protein are colored in orange, and those by the PsaB are colored in gray. Besides the main pigments involved in charge separation, there are remarkable similarities in the position of certain accessory carotenoids and chlorophylls between Photosystem II (CarD1, CarD2, ChlZ, ChlD) and Photosystem I, suggesting that these may have been present in the ancestral reaction center
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Fig1: Reaction center architecture and cofactors. a Top view of a Type II reaction center from Blastochloris viridis highlighting the position of the transmembrane helices, PDB ID: 2PRC (Lancaster and Michel 1997). b Top view of Photosystem II from Thermosynechococcus vulcanus where only the transmembrane helices from the reaction center subunits (D1 and D2) and antenna proteins (CP43 and CP47) are highlighted, PDB ID: 3ARC (Umena et al. 2011). c Top view of Photosystem I from Synechococcus elongatus, PDB ID: 1JB0 (Jordan et al. 2001). d Cofactors in the Type II reaction center from B. viridis, the pigments colored in orange are coordinated or held by the M subunit, while those in gray by the L subunit. e Cofactors in Photosystem II, only those held by the D1 (gray) and D2 (orange) proteins are shown. f Cofactors in Photosystem I, those coordinated by the PsaA protein are colored in orange, and those by the PsaB are colored in gray. Besides the main pigments involved in charge separation, there are remarkable similarities in the position of certain accessory carotenoids and chlorophylls between Photosystem II (CarD1, CarD2, ChlZ, ChlD) and Photosystem I, suggesting that these may have been present in the ancestral reaction center

Mentions: Photochemical reaction centers exist in two basic forms differentiated by some structural features and the nature of the terminal electron acceptor (Fig. 1). Type II reaction centers are found in the phototrophic members of the phylum Chloroflexi, Proteobacteria, and Gemmatimonadetes. Homodimeric Type I reaction centers are found in heliobacteria, Chlorobiales, and C. thermophilum. Cyanobacteria are the only group of photosynthetic bacteria known to carry both types of reaction centers (Govindjee and Shevela 2011): Photosystem II, the water-oxidizing enzyme, and a heterodimeric Type I reaction center, Photosystem I.Fig. 1


A fresh look at the evolution and diversification of photochemical reaction centers.

Cardona T - Photosyn. Res. (2014)

Reaction center architecture and cofactors. a Top view of a Type II reaction center from Blastochloris viridis highlighting the position of the transmembrane helices, PDB ID: 2PRC (Lancaster and Michel 1997). b Top view of Photosystem II from Thermosynechococcus vulcanus where only the transmembrane helices from the reaction center subunits (D1 and D2) and antenna proteins (CP43 and CP47) are highlighted, PDB ID: 3ARC (Umena et al. 2011). c Top view of Photosystem I from Synechococcus elongatus, PDB ID: 1JB0 (Jordan et al. 2001). d Cofactors in the Type II reaction center from B. viridis, the pigments colored in orange are coordinated or held by the M subunit, while those in gray by the L subunit. e Cofactors in Photosystem II, only those held by the D1 (gray) and D2 (orange) proteins are shown. f Cofactors in Photosystem I, those coordinated by the PsaA protein are colored in orange, and those by the PsaB are colored in gray. Besides the main pigments involved in charge separation, there are remarkable similarities in the position of certain accessory carotenoids and chlorophylls between Photosystem II (CarD1, CarD2, ChlZ, ChlD) and Photosystem I, suggesting that these may have been present in the ancestral reaction center
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4582080&req=5

Fig1: Reaction center architecture and cofactors. a Top view of a Type II reaction center from Blastochloris viridis highlighting the position of the transmembrane helices, PDB ID: 2PRC (Lancaster and Michel 1997). b Top view of Photosystem II from Thermosynechococcus vulcanus where only the transmembrane helices from the reaction center subunits (D1 and D2) and antenna proteins (CP43 and CP47) are highlighted, PDB ID: 3ARC (Umena et al. 2011). c Top view of Photosystem I from Synechococcus elongatus, PDB ID: 1JB0 (Jordan et al. 2001). d Cofactors in the Type II reaction center from B. viridis, the pigments colored in orange are coordinated or held by the M subunit, while those in gray by the L subunit. e Cofactors in Photosystem II, only those held by the D1 (gray) and D2 (orange) proteins are shown. f Cofactors in Photosystem I, those coordinated by the PsaA protein are colored in orange, and those by the PsaB are colored in gray. Besides the main pigments involved in charge separation, there are remarkable similarities in the position of certain accessory carotenoids and chlorophylls between Photosystem II (CarD1, CarD2, ChlZ, ChlD) and Photosystem I, suggesting that these may have been present in the ancestral reaction center
Mentions: Photochemical reaction centers exist in two basic forms differentiated by some structural features and the nature of the terminal electron acceptor (Fig. 1). Type II reaction centers are found in the phototrophic members of the phylum Chloroflexi, Proteobacteria, and Gemmatimonadetes. Homodimeric Type I reaction centers are found in heliobacteria, Chlorobiales, and C. thermophilum. Cyanobacteria are the only group of photosynthetic bacteria known to carry both types of reaction centers (Govindjee and Shevela 2011): Photosystem II, the water-oxidizing enzyme, and a heterodimeric Type I reaction center, Photosystem I.Fig. 1

Bottom Line: In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments.Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria.The primordial phototrophic ancestor must have had both Type I and Type II reaction centers.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Imperial College London, Exhibition Road, London, SW7 2AZ, UK. t.cardona@imperial.ac.uk.

ABSTRACT
In this review, I reexamine the origin and diversification of photochemical reaction centers based on the known phylogenetic relations of the core subunits, and with the aid of sequence and structural alignments. I show, for example, that the protein folds at the C-terminus of the D1 and D2 subunits of Photosystem II, which are essential for the coordination of the water-oxidizing complex, were already in place in the most ancestral Type II reaction center subunit. I then evaluate the evolution of reaction centers in the context of the rise and expansion of the different groups of bacteria based on recent large-scale phylogenetic analyses. I find that the Heliobacteriaceae family of Firmicutes appears to be the earliest branching of the known groups of phototrophic bacteria; however, the origin of photochemical reaction centers and chlorophyll synthesis cannot be placed in this group. Moreover, it becomes evident that the Acidobacteria and the Proteobacteria shared a more recent common phototrophic ancestor, and this is also likely for the Chloroflexi and the Cyanobacteria. Finally, I argue that the discrepancies among the phylogenies of the reaction center proteins, chlorophyll synthesis enzymes, and the species tree of bacteria are best explained if both types of photochemical reaction centers evolved before the diversification of the known phyla of phototrophic bacteria. The primordial phototrophic ancestor must have had both Type I and Type II reaction centers.

No MeSH data available.


Related in: MedlinePlus