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- Source Environment Feature Related Phylogenetic Distribution Pattern of Anoxygenic Photosynthetic Bacteria as Revealed by pufM Analysis
- Yonghui Zeng , Nianzhi Jiao
- J. Microbiol. 2007;45(3):205-212.
- DOI: https://doi.org/2541 [pii]
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Abstract
- Anoxygenic photosynthesis, performed primarily by anoxygenic photosynthetic bacteria (APB), has been supposed to arise on Earth more than 3 billion years ago. The long established APB are distributed in almost every corner where light can reach. However, the relationship between APB phylogeny and source environments has been largely unexplored. Here we retrieved the pufM sequences and related source information of 89 pufM containing species from the public database. Phylogenetic analysis revealed that horizontal gene transfer (HGT) most likely occurred within 11 out of a total 21 pufM subgroups, not only among species within the same class but also among species of different phyla or subphyla. A clear source environment feature related phylogenetic distribution pattern was observed, with all species from oxic habitats and those from anoxic habitats clustering into independent subgroups, respectively. HGT among ancient APB and subsequent long term evolution and adaptation to separated niches may have contributed to the coupling of environment and pufM phylogeny.
- Effect of Mutations of Five Conserved Histidine Residues in the Catalytic Subunit of the cbb3 Cytochrome c Oxidase on its Function
- Jeong-Il Oh
- J. Microbiol. 2006;44(3):284-292.
- DOI: https://doi.org/2384 [pii]
- 13 View
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Abstract
- The cbb3 cytochrome c oxidase has the dual function as a terminal oxidase and oxygen sensor in the photosynthetic bacterium, Rhodobacter sphaeroides. The cbb3 oxidase forms a signal transduction pathway together with the PrrBA two-component system that controls photosynthesis gene expression in response to changes in oxygen tension in the environment. Under aerobic conditions the cbb3 oxidase generates an inhibitory signal, which shifts the equilibrium of PrrB kinase/phosphatase activities towards the phosphatase mode. Photosynthesis genes are thereby turned off under aerobic conditions. The catalytic subunit (CcoN) of the R. sphaeroides cbb3 oxidase contains five histidine residues (H214, H233, H303, H320, and H444) that are conserved in all CcoN subunits of the cbb3 oxidase, but not in the catalytic subunits of other members of copper-heme superfamily oxidases. H214A mutation of CcoN affected neither catalytic activity nor sensory (signaling) function of the cbb3 oxidase, whereas H320A mutation led to almost complete loss of both catalytic activity and sensory function of the cbb3 oxidase. H233V and H444A mutations brought about the partial loss of catalytic activity and sensory function of the cbb3 oxidase. Interestingly, the H303A mutant form of the cbb3 oxidase retains the catalytic function as a cytochrome c oxidase as compared to the wild-type oxidase, while it is defective in signaling function as an oxygen sensor. H303 appears to be implicated in either signal sensing or generation of the inhibitory signal to the PrrBA two-component system.
- Functional Characterization of the Gene Encoding UDP-glucose: Tetrahydrobiopterin [alpha]-Glucosyltransferase in Synechococcus sp. PCC 7942
- En-Young Cha , Jeong Soon Park , Sireong Jeon , Jin Seon Kong , Yong Kee Choi , Jee-Youn Ryu , Youn-Il Park , Young Shik Park
- J. Microbiol. 2005;43(2):191-195.
- DOI: https://doi.org/2162 [pii]
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Abstract
- In this study, we attempted to characterize the Synechococcus sp. PCC 7942 mutant resultant from a disruption in the gene encoding UDP-glucose: tetrahydrobiopterin [alpha]-glucosyltransferase (BGluT). 2D-PAGE followed by MALDI-TOF mass spectrometry revealed that phycocyanin rod linker protein 33K was one of the proteins expressed at lower level in the BGluT mutant. BGluT mutant cells were also determined to be more sensitive to high light stress. This is because photosynthetic O_2 exchange rates were significantly decreased, due to the reduced number of functional PSIs relative to the wild type cells. These results suggested that, in Synechococcus sp. PCC 7942, BH4-glucoside might be involved in photosynthetic photoprotection.
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