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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

Structural comparisons of Type II reaction center proteins. a Overlap of D1 (gray) and L (cyan) subunits. Structural regions that are unique to D1 and D2 are highlighted in orange. b, c The interactions of ancillary subunits with a protein fold in D1 and D2 (orange). In D1, this region evolved to allow protein–protein interactions with the PsbI, PsbO, and CP43 subunits. In D2, it allows interactions with the Cytochrome b559 and PsbX. The presence of this fold in D1 and D2 suggests that before the evolution of oxygenic photosynthesis, the ancestral Photosystem II was already interacting with ancillary subunits. d A unique loop (orange) only present in D1 and D2. This region contains a tyrosine that coordinates the bicarbonate ligand of the non-heme Fe2+. e, f The C-terminal extension of D1 and D2 (orange) essential for the assembly and coordination of the Mn4CaO5 cluster. This C-terminal extension contains a parallel alpha helix in both subunits, suggesting that it was present in the ancestral Photosystem II before the D1 and D2 divergence
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Fig4: Structural comparisons of Type II reaction center proteins. a Overlap of D1 (gray) and L (cyan) subunits. Structural regions that are unique to D1 and D2 are highlighted in orange. b, c The interactions of ancillary subunits with a protein fold in D1 and D2 (orange). In D1, this region evolved to allow protein–protein interactions with the PsbI, PsbO, and CP43 subunits. In D2, it allows interactions with the Cytochrome b559 and PsbX. The presence of this fold in D1 and D2 suggests that before the evolution of oxygenic photosynthesis, the ancestral Photosystem II was already interacting with ancillary subunits. d A unique loop (orange) only present in D1 and D2. This region contains a tyrosine that coordinates the bicarbonate ligand of the non-heme Fe2+. e, f The C-terminal extension of D1 and D2 (orange) essential for the assembly and coordination of the Mn4CaO5 cluster. This C-terminal extension contains a parallel alpha helix in both subunits, suggesting that it was present in the ancestral Photosystem II before the D1 and D2 divergence

Mentions: Despite D1 and D2 sharing only about 33 % sequence identity along the most conserved regions, they share not only remarkable structural similarities, but also features that distinguish them from their L/M cousins. There are three regions shared by D1 and D2 that are not present in L and M subunits (see Fig. 4a) (Ferreira et al. 2004; Umena et al. 2011). These are:Fig. 4


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

Cardona T - Photosyn. Res. (2014)

Structural comparisons of Type II reaction center proteins. a Overlap of D1 (gray) and L (cyan) subunits. Structural regions that are unique to D1 and D2 are highlighted in orange. b, c The interactions of ancillary subunits with a protein fold in D1 and D2 (orange). In D1, this region evolved to allow protein–protein interactions with the PsbI, PsbO, and CP43 subunits. In D2, it allows interactions with the Cytochrome b559 and PsbX. The presence of this fold in D1 and D2 suggests that before the evolution of oxygenic photosynthesis, the ancestral Photosystem II was already interacting with ancillary subunits. d A unique loop (orange) only present in D1 and D2. This region contains a tyrosine that coordinates the bicarbonate ligand of the non-heme Fe2+. e, f The C-terminal extension of D1 and D2 (orange) essential for the assembly and coordination of the Mn4CaO5 cluster. This C-terminal extension contains a parallel alpha helix in both subunits, suggesting that it was present in the ancestral Photosystem II before the D1 and D2 divergence
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig4: Structural comparisons of Type II reaction center proteins. a Overlap of D1 (gray) and L (cyan) subunits. Structural regions that are unique to D1 and D2 are highlighted in orange. b, c The interactions of ancillary subunits with a protein fold in D1 and D2 (orange). In D1, this region evolved to allow protein–protein interactions with the PsbI, PsbO, and CP43 subunits. In D2, it allows interactions with the Cytochrome b559 and PsbX. The presence of this fold in D1 and D2 suggests that before the evolution of oxygenic photosynthesis, the ancestral Photosystem II was already interacting with ancillary subunits. d A unique loop (orange) only present in D1 and D2. This region contains a tyrosine that coordinates the bicarbonate ligand of the non-heme Fe2+. e, f The C-terminal extension of D1 and D2 (orange) essential for the assembly and coordination of the Mn4CaO5 cluster. This C-terminal extension contains a parallel alpha helix in both subunits, suggesting that it was present in the ancestral Photosystem II before the D1 and D2 divergence
Mentions: Despite D1 and D2 sharing only about 33 % sequence identity along the most conserved regions, they share not only remarkable structural similarities, but also features that distinguish them from their L/M cousins. There are three regions shared by D1 and D2 that are not present in L and M subunits (see Fig. 4a) (Ferreira et al. 2004; Umena et al. 2011). These are:Fig. 4

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