The Light-Harvesting Polypeptides of<i>Rhodopseudomonas sphaeroides</i>R-26.1. I. Isolation, Purification and Sequence Analyses

Theiler, Rolf; Suter, Franz; Wiemken, V.; Zuber, Herbert

doi:10.1515/bchm2.1984.365.2.703

Cited by 95 publications

(35 citation statements)

References 25 publications

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“…The resulting fractions 1 and 2 were purified by rechromatography under the same conditions. The highly purified polypeptides 1 and 2 had the amino acid compositions of the B870a and B800-850a polypeptides, respectively (33)(34)(35).…”

Section: Resultsmentioning

confidence: 99%

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Localization of reaction center and B800-850 antenna pigment proteins in membranes of Rhodobacter sphaeroides

et al. 1988

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The localization of the N-and C-terminal regions of pigment-binding polypeptides of the bacterial photosynthetic apparatus of Rhodobacter sphaeroides was investigated by proteinase K treatment of chromatophore and spheroplast-derived vesicles and amino acid sequence determination. Under conditions of proteinase K treatment of chromatophores, which left the in vivo absorption spectrum and the membrane intact, 15 and 46 amino acyl residues from the N-terminal regions of the L and M subunits, respectively, of the reaction center polypeptides were removed. The N termini are therefore exposed on the cytoplasmic surface of the membrane. The C-terminal domain of the light-harvesting B800-850a and B870a polypeptides was found to be exposed on the periplasmic surface of the membrane. A total of 9 and 13 amino acyl residues were cleaved from the B800-850a and B870a polypeptides, respectively, when spheroplasts were treated with proteinase K. The N-terminal regions of the a polypeptides were not digested in either membrane preparation and were apparently protected from proteolytic attack. Seven N-terminal amino acyl residues of the B800-850,1 polypeptide were removed after the digestion of chromatophores. C-terminal residues were not removed after the digestion of chromatophores or spheroplasts. The C termini seem to be protected from protease attack by interaction with the membrane. Therefore, the N-terminal regions of the , polypeptides are exposed on the cytoplasmic membrane surface. The C termini of the B polypeptides are believed to point to the periplasmic space.The photosynthetic apparatus of Rhodobacter sphaeroides is located in an intracytoplasmic membrane system formed by invaginations of the cytoplasmic membrane (15). The major components of the photosynthetic apparatus are the light-harvesting (LH) or antenna pigment-protein complexes and the photochemical reaction center (RC), which are present as integral membrane particles (14). The absorption of light energy by LH complexes creates excited singlet states which migrate over the antennae downhill to the RC where they are trapped and converted into a membrane potential difference and a redox potential difference. This conversion drives a cyclic electron transport and the formation of a proton gradient across the membrane (16).The bacteriochlorophyll and carotenoid pigments are bound in stoichiometric ratios to the polypeptides of the three complexes: RC and the LH complexes B870 and B800-850, named according to their near-infrared absorption bands. In each LH complex, two different polypeptides bind noncovalently two or three bacteriochlorophyll and one or two carotenoid molecules. The axes of the pigment molecules have a strict orientation relative to the plane of the membrane (6, 18, 25). The pigment-binding polypeptides span the membrane once by a transmembrane a helix of hydrophobic amino acyl residues in LH complexes (5). The RC subunits M and L (RC-M and RC-L, respectively) span the membrane five times each (1,13,22,39). The N-and C-terminal domains of L...

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Section: Resultsmentioning

confidence: 99%

“…The N-and C-terminal domains of LH and RC polypeptides and the loops between the a helices of RC polypeptides are proposed to be exposed on the membrane surface (1,13,21,(36)(37)(38)(39). The primary structures of the LH and RC polypeptides from R. sphaeroides have been determined (2,26,(33)(34)(35)(36)(37)(38). LH * Corresponding author.…”

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confidence: 99%

Localization of reaction center and B800-850 antenna pigment proteins in membranes of Rhodobacter sphaeroides

et al. 1988

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“…Because there is only one copy of the B800-850-P polypeptide gene in the R. sphaeroides genome (27), it is likely that the difference between 15B and 15C is due to posttranslational events. Theiler et al (42,43) previously demonstrated heterogeneity in the amino termini of B800-850-P polypeptide; some contained amino-terminal methionine and the remainder had blocked amino-terminal threonine residues. This would be consistent with posttranslational modification of the P subunit.…”

Section: Discussionmentioning

confidence: 99%

Physiological and structural analysis of light-harvesting mutants of Rhodobacter sphaeroides

1988

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Two mutants of Rhodobacter sphaeroides defective in formation of light-harvesting spectral complexes were examined in detail. Mutant RS103 lacked the B875 spectral complex despite the fact that substantial levels of the B875-oa polypeptide (and presumably the ,( polypeptide) were present. The B800-850 spectral complex was derepressed in RS103, even at high light intensities, and the growth rate was near normal at high light intensity but decreased relative to the wild type as the light intensity used for growth decreased. Mutant RS104 lacked colored carotenoids and the B800-850 spectral complex, as well as the cognate apoproteins. This strain grew normally at high light intensity and, as with RS103, the growth rate decreased as the light intensity used for growth decreased. At very low light intensities, however, RS104 would grow, whereas RS103 would not. Structural analysis of these mutants as well as others revealed that the morphology of the intracytoplasmic membrane invaginations is associated with the presence or absence of the B800-850 complex as well as of carotenoids. A low-molecular-weight intracytoplasmic membrane polypeptide, which may play a role in B800-850 complex formation, is described, as is a 62,000-dalton polypeptide whose abundance is directly related to light intensity as well as the absence of either of the light-harvesting spectral complexes. These data, obtained from studies of mutant strains and the wild type, are discussed in light of photosynthetic membrane formation and the abundance of spectral complexes per unit area of membrane. Finally, a method for the bulk preparation of the B875 complex from wild-type strain 2.4.1 is reported.

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“…The 7.4 kDa polypeptide shows the same three domain structures as the intramembrane antenna polypeptides of other purple bacteria [13][14][15][16][17][18][19] ( fig.4). As compared to the sequences of purple non-sulfur bacteria the 7.4 kDa polypeptide (65 amino acid residues) exhibits an extended Cterminal domain.…”

Section: Discussionmentioning

confidence: 88%

“…A B800/1020 antenna complex has been isolated and characterized [5] as consisting of three polypeptides differing in size [4,5]. In the case of purple non-sulfur bacteria a great number of lightharvesting polypeptides from various species have been isolated and their primary structures have been determined [13][14][15][16][17][18][19][20]. These antenna polypeptides exhibit a histidine residue in the central hydrophobic domain, assigned as the fifth ligand to the Mg atom of bacteriochlorophyll.…”

Section: Introductionmentioning

confidence: 99%

A new possible binding site for bacteriochlorophyll b in a light‐harvesting polypeptide of the bacterium Ectothiorhodospira halochloris

Wagner-Huber¹,

Brunisholz²,

Bissig³

et al. 1988

FEBS Letters

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Whole cells from Ectothiorhodospira halochloris were extracted with an organic solvent mixture. At least five small hydrophobic polypeptides representing most probably the light harvesting polypeptides were purified by gel filtration and consecutive FPLC-RP chromatography. The complete amino acid sequence of a 7.4 kDa polypeptide was determined. The polypeptide shows a three domain structure, indicative of an integral membrane protein, similar to the structure of the light-harvesting polypeptides from purple non-sulfur bacteria. Sequence homologies to the fl-LHPs of purple bacteria range from 23. !% to 36.4~;. The conserved intramembrane located histidine residue of the antenna polypeptides of purple non-sulfur bacteria, assigned as the possible binding site for bacteriochlorophyll, was found to be replaced by asparagine.Purple bacteria; Bacteriochlorophyll b; Light-harvesting polypeptide; Amino acid sequence; (Ectothiorhodospira halochloris)

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The Light-Harvesting Polypeptides ofRhodopseudomonas sphaeroidesR-26.1. I. Isolation, Purification and Sequence Analyses

Abstract: Four low-molecular-mass polypeptides were isolated and purified from chromatophore membranes of Rhodopseudomonas spliaeroides blue-green mutant R-26.

Cited by 95 publications

References 25 publications

Localization of reaction center and B800-850 antenna pigment proteins in membranes of Rhodobacter sphaeroides

Localization of reaction center and B800-850 antenna pigment proteins in membranes of Rhodobacter sphaeroides

Physiological and structural analysis of light-harvesting mutants of Rhodobacter sphaeroides

A new possible binding site for bacteriochlorophyll b in a light‐harvesting polypeptide of the bacterium Ectothiorhodospira halochloris

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