Amino acid sequence of the cytochrome subunit of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis (original) (raw)
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Journal of Biological Chemistry, 1999
The nucleotide sequence of the puf operon, which contains the genes encoding the B870 light-harvesting protein and the reaction center complex of the purple photosynthetic bacterium, Rhodovulum sulfidophilum, was determined. The operon, which consisted of six genes, pufQ, pufB, pufA, pufL, pufM, and pufC, is a new variety in photosynthetic bacteria in the sense that pufQ and pufC coexist. The amino acid sequence of the cytochrome subunit of the reaction center deduced from the pufC sequence revealed that this cytochrome contains only three possible heme-binding motifs; the heme-1binding motif of the corresponding tetraheme cytochrome subunits was not present. This is the first exception of the "tetraheme" cytochrome family in purple bacteria and green filamentous bacteria. The pufC sequence also revealed that the sixth axial ligands to heme-1 and heme-2 irons were not present in the cytochrome either. This cytochrome was actually detected in membrane preparation as a 43-kDa protein and shown to associate functionally with the photosynthetic reaction center as the immediate electron donor to the photo-oxidized special pair of bacteriochlorophyll. This new cytochrome should be useful for studies on the role of each heme in the cytochrome subunit of the bacterial reaction center and the evolution of proteins in photosynthetic electron transfer systems.
The EMBO Journal, 1986
The 'light' (L) and the 'medium' (M) subunits of the photosynthetic reaction centre from Rhodopseudomonas viridis were isolated and their amino-terminal sequences, as well as the sequences of several chymotryptic peptides, determined. Rps. viridis DNA was cloned in the Escherichia coli plasmid pBR322. Mixed oligonucleotide probes derived from the amino acid sequences were synthesised and utilised to isolate one clone which contained the genes for the L and M subunits of the reaction centre as well as the a and ,B subunits of the light-harvesting complex and part of the gene for the reaction centre cytochrome. The nucleotide sequences of the L and M subunit genes and the derived amino acid sequences are presented. The L subunit consists of 273 amino acids and has a mol. wt of 30 571. The M subunit consists of 323 amino acids and has a mol. wt of 35 902. The primary structure is discussed in the light of the recently published secondary and tertiary structure which has shown that both subunits contain five membrane-spanning helices.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1984
The amino-terminal sequences have been determined by Edman degradation for the reaction center polypeptides from a carotenoidless mutant of Rhodopseudomonas capsulat~ Individual polypeptides were isolated by preparative electrophoresis and electroelution. By comparison with the sequences deduced from the DNA (Youvan, D.C., Alherti, M., Begush, H., Bylina, E.J. and Hearst, J.E. (1984) Proc. Natl. Acad. Sci. USA 81, 189-192) we conclude that the M and L subunits are processed so as to remove the amino-terminal methionine, whereas the H subunit is not processed at the amino-terminus after translation. None of the subunits is synthesized with a significant amino-terminal extension peptide.
Nobel lecture. The photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis
The EMBO journal, 1989
In our lectures we first describe the history and methods of membrane protein crystallization, before we show how the structure of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis was solved. Then the structure of this membrane protein complex is correlated with its function as a light-driven electron pump across the photosynthetic membrane. Finally we draw conclusions on the structure of the photosystem II reaction centre from plants and discuss the aspects of membrane protein structure. Sections 1 (crystallization), 4 (conclusions on the structure of photosystem II reaction centre and evolutionary aspects) and 5 (aspects of membrane protein structure) were presented and written by H.M., Sections 2 (determination of the structure) and 3 (structure and function) by J.D. We have arranged the paper in this way in order to facilitate continuous reading.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1986
Electron donors to photo-oxidized reaction centers were studied in Rhodopseudomonas palustds and Rhodopseudomonas acidophila using whole cells, membrane preparations and reaction center-B880 complexes. In Rps. palustris, no hemes were tightly bound to the reaction center complex and cytochrome c 2 was presumed to be the direct electron donor to the photo-oxidized bacteriochlorophyll dimer in whole cells. Cytochrome c 2 was lost in the membrane preparation obtained after a French press disruption of cells and mammalian cytochrome c added externally was oxidized by illumination. On the other hand, in Rps. acidopMla, the reaction center complex was tightly associated with four cytochrome hemes, two of which were identified as cytochrome c-553 (Era7 = 110 mV) and the other two as cytochrome c-555 (Era7-360 mV). When both cytochromes were reduced prior to illumination, cytochrome c-553 was rapidly oxidized by a flash. Cytochrome c-555 was the one oxidized by a flash when cytochrome c-553 was already oxidized before activation. Cytochrome c 2 was presumed to be the electron donor to the photo-oxidized cytochrome c-555 in whole cells. In the membrane preparation, a rapid electron transfer was observed from externally added mammalian cytochrome c to photooxidized cytochrome c-555. A possible phylogenetic correlation between the absence of the tightly bound cytochromes and a long class of cytochrome c 2 (Dickerson, R.E. (1980) Nature 283, 210-212) is discussed.
Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1998
The isolation and amino acid sequences of two cytochromes c-552 from the thermotolerant bacterium Rhodospirillum ( ) R. centenum have been determined. They are very similar to one another with 85% identity. They are homologous to the ( ) cytochromes c from purple bacteria with approximately 67% identity to that from Rhodopseudomonas Rps. palustris 2 compared to only 42% identity with others of the c subclass. In addition, they share an unusual six-residue insertion with 2 Rps. palustris cytochrome c not found in any other cytochrome. The relationship with Rps. palustris is thus highly 2 significant. The redox potentials of the R. centenum isozymes are 293 and 316 mV. Although the proteins have strongly different iso-electric points, both have three conserved lysine residues at the proposed site of electron transfer. These results suggest that they may be functionally interchangeable. q
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2001
The cytochrome subunit bound to the photosynthetic reaction center (RC) complex in Rhodovulum sulfidophilum lacks one heme-binding motif (CXXCH) out of four motifs found in other purple bacteria resulting in the absence of the most distal heme from the RC-core complex (S. Masuda et al., J. Biol. Chem. 274 (1999) 10795). Cytochrome c 2 , which acts as the electron donor to the RC was purified, and its gene was cloned and sequenced. The redox midpoint potential of cytochrome c 2 was determined to be E m = 357 mV. The photo-oxidation and re-reduction of purified cytochrome c 2 were observed in the presence of membrane preparations. Flash-induced photo-oxidation and re-reduction of the RC-bound cytochrome were also observed in intact cells. Despite the unusual nature of the RC-bound cytochrome subunit, the cyclic electron transfer system in Rdv. sulfidophilum was shown to be similar to those in other purple bacteria.
The Photosynthetic Reaction Centre from the Purple Bacterium Rhodopseudomonas viridis
Bioscience Reports, 2004
We first describe the history and methods of membrane protein crystallization, and show how the structure of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis was solved. The structure of this membrane protein complex is correlated with its function as a light-driven electron pump across the photosynthetic membrane. Finally we draw conclusions on the structure of the photosystem II reaction centre from plants and discuss the aspects of membrane protein structure.
Cytochrome c2 is not Essential for Photosynthetic Growth of Rhodopseudomonas capsulata
Proceedings of The National Academy of Sciences, 1986
The structural gene for cytochrome c2 (cycA) of the photosynthetic bacterium Rhodopseudomonas capsulata has been cloned, and the nucleotide and deduced polypeptide sequences have been determined. Compared with the known amino acid sequence of the purified cytochrome c2, the nucleotide sequence corresponding to the N-terminal part of the cycA gene product indicates the presence of a putative 21 amino acid signal sequence. Thus, cytochrome c2 may be synthesized as a precursor which is processed during its secretion to the periplasm. Insertion and insertion-deletion mutations were constructed in vitro and the chromosomal