A comparison of the primary structures of the two B800‐850‐apoproteins from wild‐type <i>Rhodopseudomonas sphaeroides</i> strain 2.4.1 and a carotenoidless mutant strain R26.1

Theiler, Rolf; Suter, Franz; Zuber, Herbert; Cogdell, Richard J.

doi:10.1016/0014-5793(84)80742-5

Cited by 57 publications

(46 citation statements)

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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%

“…tides have been sequenced, and their molecular weights are 6,809 and 5,457, respectively (41). Detergent-purified B800-850 complexes (7) contain two polypeptide subunits, B800-850-a and B800-850-P, which by amino acid sequence are 5,599 and 5,448 daltons, respectively (43). There are 6 molecules of Bchl per two pairs of polypeptide subunits while the Bchl/carotenoid ratio is 3:1 (50).…”

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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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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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

1988

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“…Recently, more than ten of the antenna apoproteins from five different species of the photosynthetic bacteria have been sequenced (Brunisholz et al, 1984a(Brunisholz et al, , 1984bGogel et al, 1983;Tadros et al, 1983;Theiler et a!., 1984;Brunisholz et al, 1985). In general all the polypeptide subunits contain three distinct structural domains: a central hydrophobic core and which is flanked by rather polar N-and C-terminal regions.…”

Section: Introductionmentioning

confidence: 99%

Circular Dichroism of Light‐harvesting Complexes From Purple Photosynthetic Bacteria*

Cogdell

Scheer

1985

Photochem & Photobiology

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Abstract-The CD spectra of a range of antenna complexes from several different species of purple photosynthetic bacteria were recorded in the wavelength range of 190 to 930 nm. Analysis of the far UV CD (190 to 250 nm) showed that in each case except for the B800-850 from Chr. vinosum the secondary structure of the light-harvesting complexes contains a large amount of a-helix ( 2 5 0 % ) and very little p-pleated sheet. This confirms the predictions of the group of Zuber of a high a-helical content based upon consideration of the primary structures of several antenna apoproteins. The CD spectra from the carotenoids and the bacteriochlorophylls show considerable variations depending upon the type of antenna complex. The different amplitude ratios in the CD spectrum for the bacteriochlorophyll Qy, Qx and Soret bands indicate not only different degrees of exciton coupling, but also a strong and variable hyperchromism (Scherz and Parson, 1984a, b).

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“…The minimal structure comprising the B800-850 spectral complex consists of two each of two small hydrophobic polypeptides, the B800-850-, and -a polypeptides (5,448 and 5,599 daltons [Da], respectively [38]), six molecules of Bchl, and three molecules of carotenoid (22). The purified B800-850 complex in R. sphaeroides was found (23) not to be associated with a third polypeptide as observed for the purified B800-850 complex from Rhodobacter capsulatus (15).…”

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Posttranscriptional control of puc operon expression of B800-850 light-harvesting complex formation in Rhodobacter sphaeroides

1989

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The puc operon of Rhodobacter sphaeroides comprises the pucBA structural genes which encode B800-850 light-harvesting ,I and a polypeptides, respectively. Northern (RNA) blot hybridization analysis of puc operon expression has identified two pucBA-specific transcripts. The small (0.5-kilobase [kb]) transcript encodes the 0i and a polypeptides and, under photoheterotrophic growth conditions, was approximately 200-fold more abundant than the large (2.3-kb) transcript. The 5' end of the 0.5-kb transcript was mapped at 117 nucleotides upstream from the start ofpucB. The 3' ends of the 0.5-kb transcript were mapped to two adjacent nucleotides, which follow a stem-loop structure immediately 3' to the pucA stop codon. Two mutant strains, PUC705-BA and PUC-Pv, were constructed by replacement of the pucBA genes and adjacent DNA in the former case or by insertional interruption of the DNA downstream of the pucBA genes in the latter case. The two mutant strains were devoid of B800-850 complexes during photosynthetic growth but were otherwise apparently normal. The B800-850-phenotype of both PUC705-BA and PUC-Pv was not complemented in trans with a 2.5-kb PstI restriction endonuclease fragment extending from 0.75 kb upstream of pucBA to 1.3 kb downstream of pucBA, despite the presence of the 0.5-kb pucBA-specific transcript. Both of the mutant strains, however, showed restoration of B800-850 expression with a 10.5-kb EcoRI restriction endonuclease fragment in trans encompassing the 2.5-kb PstI fragment. Western immunoblot analysis revealed no B800-850-I polypeptide as well as no polypeptide designated 15A in either mutant. Nonetheless, under photoheterotrophic growth conditions, the 0.5-kb pucBA-specific transcript was present in PUC-Pv, although no 2.3-kb transcript was detectable. We suggest that the DNA region immediately downstream of pucBA encodes a gene product(s) essential for translational or posttranslational expression of the B800-850 0i and a polypeptides.The purple nonsulfur photosynthetic bacterium Rhodobacter sphaeroides is an ideal system for the study of bacterial photosynthesis as well as membrane development (22). In response to lower partial pressures of oxygen, this bacterium can form the unique photosynthetic membrane system referred to as the intracytoplasmic membrane (ICM), in addition to the normal gram-negative membrane system found during aerobic growth (4, 17). The three major bacteriochlorophyll (Bchl)-protein complexes found in the ICM are the light-harvesting complexes B800-850 (LHII) and B875 (LHI) and the reaction center (RC) complex. The LH complexes capture and funnel photons as excitation energy for the photo-induced reversible oxidation-reduction of the RC, ultimately giving rise to chemical energy (32). The fixed photosynthetic unit is composed of B875 and RC complexes (1, 5) encoded by the puf(42) and puh (11) operons. The ratio of B875 to RC complexes is fixed at approximately 12:1 to 15:1 irrespective of the incident light intensity. On the other hand, B800-850 complex formation is va...

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A comparison of the primary structures of the two B800‐850‐apoproteins from wild‐type Rhodopseudomonas sphaeroides strain 2.4.1 and a carotenoidless mutant strain R26.1

Cited by 57 publications

References 12 publications

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

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

Circular Dichroism of Light‐harvesting Complexes From Purple Photosynthetic Bacteria*

Posttranscriptional control of puc operon expression of B800-850 light-harvesting complex formation in Rhodobacter sphaeroides

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