Single core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: structural implications and relations to other photosystems.

Liebl, Ursula; Mockensturm-Wilson, Melissa; Trost, Jeffrey T.; Brune, Daniel C.; Blankenship, Robert E.; Vermaas, Wim F. J.

doi:10.1073/pnas.90.15.7124

Cited by 171 publications

(169 citation statements)

References 21 publications

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“…SSDI 0014-5793(94)00724-l products) 1193. A similar result was obtained from HeZiobacillus mobilis [20]. This implies that these two organisms have reaction centres that are protein homodimers [20,21] rather than heterodimers.…”

Section: Introductionsupporting

confidence: 75%

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The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

et al. 1994

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The radical cation P840" was studied in frozen suspensions of Chlorobium limicolu f. sp. thiosulphatophilum membranes using ENDOR and Special TRIPLE spectroscopies. The spectra show that P840" arises from a bacteriochlorophyll a 'special' pair with a highly symmetrical distribution of electron spin density between the constituent bacteriochlorophylls. Special TRIPLE spectroscopy has resolved the separate contributions of the two halves of the pair and revealed small deviations from a 1 : 1 electron spin density distribution. Nevertheless P840" appears to come the closest yet to the symmetrical 'dimer' originally proposed for the structure of the primary donor radical cation (P870") in purple non-sulphur photosynthetic bacteria.

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Section: Introductionsupporting

confidence: 75%

“…A similar result was obtained from HeZiobacillus mobilis [20]. This implies that these two organisms have reaction centres that are protein homodimers [20,21] rather than heterodimers. A protein homodimer reaction centre in C. thiosulphatophilum [21] would probably place P840 in a highly symmetrical environment.…”

Section: Introductionsupporting

confidence: 75%

The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

et al. 1994

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“…The RC gene pshA is located among the major group of bch genes. Although this gene was previously sequenced from the same strain used in our study (15), our analysis indicated several variations from the published sequence, including four frame shifts that resulted in an alteration of 34 amino acid codons (5.5% of the entire sequence) near the center and the C terminus of the protein. There is also a putative rho-independent termination site located in the intervening sequence between pshA and bchM, indicating that pshA may not be cotranscribed with the large cluster of downstream bch genes.…”

Section: Resultsmentioning

confidence: 87%

Tracking molecular evolution of photosynthesis by characterization of a major photosynthesis gene cluster from Heliobacillus mobilis

Xiong

Inoue

Bauer

1998

Proc. Natl. Acad. Sci. U.S.A.

172

106

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A DNA sequence has been obtained for a 35.6-kb genomic segment from Heliobacillus mobilis that contains a major cluster of photosynthesis genes. A total of 30 ORFs were identified, 20 of which encode enzymes for bacteriochlorophyll and carotenoid biosynthesis, reaction-center (RC) apoprotein, and cytochromes for cyclic electron transport. Donor side electron-transfer components to the RC include a putative RC-associated cytochrome c 553 and a unique four-large-subunit cytochrome bc complex consisting of Rieske Fe-S protein (encoded by petC), cytochrome b 6 (petB), subunit IV (petD), and a diheme cytochrome c (petX). Phylogenetic analysis of various photosynthesis gene products indicates a consistent grouping of oxygenic lineages that are distinct and descendent from anoxygenic lineages. In addition, H. mobilis was placed as the closest relative to cyanobacteria, which form a monophyletic origin to chloroplast-based photosynthetic lineages. The consensus of the photosynthesis gene trees also indicates that purple bacteria are the earliest emerging photosynthetic lineage. Our analysis also indicates that an ancient gene-duplication event giving rise to the paralogous bchI and bchD genes predates the divergence of all photosynthetic groups. In addition, our analysis of gene duplication of the photosystem I and photosystem II core polypeptides supports a ''heterologous fusion model'' for the origin and evolution of oxygenic photosynthesis.Bacterial photosynthesis is found in five eubacterial phyla: cyanobacteria, purple bacteria, heliobacteria, green sulfur bacteria, and green nonsulfur bacteria. Analysis of photosystems from purple and green nonsulfur bacteria shows that these organisms synthesize primitive photosystems that are ancestral to the more complex oxygen-evolving photosystem II (PSII) from cyanobacteria and chloroplasts (1). Additional studies of heliobacteria and green sulfur bacteria indicate that they synthesize photosystems that are ancestral to the photosystem I (PSI) complex from cyanobacteria and chloroplasts (2).With the exception of the sequence analysis of PSI and PSII structural polypeptides, there is little information on the origin and evolution of photosynthesis. Complete sequence information on photosynthesis genes is only available for the purple nonsulfur bacterium, Rhodobacter capsulatus, which has a major clustering of photosynthesis genes (3), and for the cyanobacterium Synechocystis sp. PCC 6803, for which sequence analysis has been completed for the entire chromosome. Information on photosynthesis genes from the three other eubacterial photosynthetic phyla is limited mainly to the reaction-center (RC) core polypeptides and a few cytochromes.With the aim of providing more substantive information on the evolution of photosynthesis, we have undertaken an extensive characterization of photosynthesis genes from Heliobacillus mobilis. A gene cluster was found to encode enzymes for bacteriochlorophyll and carotenoid biosynthesis, as well as the RC core polypeptide and cytochromes i...

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“…Due to this symmetry, the obvious similarity of the PsaA and PsaB polypeptides (Ϸ45-50% identical throughout their length; ref. 3) and the fact that the bacterial type I reaction centers are homodimers (4,5), the possibility of two parallel electron transfer pathways up to F X should be considered. However, based on the structural analogies of the core of PS I to the purple bacteria reaction center, which suggested a common evolutionary origin for all photosynthetic reaction centers (6), it has been generally thought that electron transport in PS I is unidirectional, as it is in the type II reaction centers.…”

mentioning

confidence: 99%

Evidence for two active branches for electron transfer in photosystem I

Guergova-Kuras

Boudreaux

Joliot

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

318

282

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All photosynthetic reaction centers share a common structural theme. Two related, integral membrane polypeptides sequester electron transfer cofactors into two quasi-symmetrical branches, each of which incorporates a quinone. In type II reaction centers [photosystem (PS) II and proteobacterial reaction centers], electron transfer proceeds down only one of the branches, and the mobile quinone on the other branch is used as a terminal acceptor. PS I uses iron-sulfur clusters as terminal acceptors, and the quinone serves only as an intermediary in electron transfer. Much effort has been devoted to understanding the unidirectionality of electron transport in type II reaction centers, and it was widely thought that PS I would share this feature. We have tested this idea by examining in vivo kinetics of electron transfer from the quinone in mutant PS I reaction centers. This transfer is associated with two kinetic components, and we show that mutation of a residue near the quinone in one branch specifically affects the faster component, while the corresponding mutation in the other branch specifically affects the slower component. We conclude that both electron transfer branches in PS I are active.

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Single core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: structural implications and relations to other photosystems.

Cited by 171 publications

References 21 publications

The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

Tracking molecular evolution of photosynthesis by characterization of a major photosynthesis gene cluster from Heliobacillus mobilis

Evidence for two active branches for electron transfer in photosystem I

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Single core polypeptide in the reaction center of the photosynthetic bacterium Heliobacillus mobilis: structural implications and relations to other photosystems.

Cited by 171 publications

References 21 publications

The electronic structure of P840+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

The electronic structure of P840+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

Tracking molecular evolution of photosynthesis by characterization of a major photosynthesis gene cluster from Heliobacillus mobilis

Evidence for two active branches for electron transfer in photosystem I

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The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre

The electronic structure of P840^+• The primary donor of the Chlorobium limicola f. sp. thiosulphatophilum photosynthetic reaction centre