Isolation and characterisation of the different B800–850 light-harvesting complexes from low- and high-light grown cells of Rhodopseudomonas palustris, strain 2.1.6

Evans, Mark B.; Hawthornthwaite, A. M.; Cogdell, Richard J.

doi:10.1016/0005-2728(90)90008-r

Cited by 55 publications

(68 citation statements)

References 13 publications

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“…BChls-a possessing a GG, DHGG, THGG or Phy substituent were isolated in 14.9, 6.8, 17.7 and 56.8 mg, respectively. The 600 MHz 1 H NMR and 150 MHz 13 C NMR spectra of each BChl-a were recorded in chloroform-d (Merck, Darmstadt, Germany) containing 1% (v/v) pyridined 5 (Cambridge Isotope Laboratories, MA, USA) using a JEOL ECA-600 NMR spectrometer (JEOL, Akishima, Japan); tetramethylsilane was used as an internal standard. A set of assignments of 1 H signals was obtained by correlation spectroscopy (COSY) and rotating frame Overhauser enhancement spectroscopy (ROESY) spectra.…”

Section: Isolation and Structural Determination Of Each Bchl-amentioning

confidence: 99%

“…A set of assignments of 1 H signals was obtained by correlation spectroscopy (COSY) and rotating frame Overhauser enhancement spectroscopy (ROESY) spectra. A set of assignments of 13 C signals was obtained using distortionless enhancement polarization transfer (DEPT), heteronuclear multiplequantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) spectra.…”

Section: Isolation and Structural Determination Of Each Bchl-amentioning

confidence: 99%

“…The DEPT spectra using 90°and 135°pulses were also used to differentiate the primary, secondary, tertiary and quaternary carbon atoms, and to confirm the assignments of 13 C signals (see Figures S2-5 in Supporting Information for the DEPT spectra of BChls-a #1 to #4). Fig.…”

Section: Structural Determination Of Propionate-type Esters In Bchls-mentioning

confidence: 99%

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Structural determination of dihydro‐ and tetrahydrogeranylgeranyl groups at the 17‐propionate of bacteriochlorophylls‐a

2006

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In the final stage of bacteriochlorophyll (BChl) biosynthesis, the presence of BChl-a molecules possessing dihydrogeranylgeranyl and tetrahydrogeranylgeranyl groups at the 17-propionate has been reported. However, the molecular structures of such BChls-a have not yet been determined in terms of the positions of C‚C double bonds in the 17 2 -ester. In this study, we isolated significant amounts of such pure BChls-a from Rhodopseudomonas palustris and determined their structures by both mass spectrometry and 1 H and 13 C NMR spectroscopy. The determined structures enable us to discuss a stepwise reduction from a geranylgeranyl to phytyl substituent.

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Section: Isolation and Structural Determination Of Each Bchl-amentioning

confidence: 99%

Section: Isolation and Structural Determination Of Each Bchl-amentioning

confidence: 99%

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Structural determination of dihydro‐ and tetrahydrogeranylgeranyl groups at the 17‐propionate of bacteriochlorophylls‐a

2006

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“…In the case of the most studied purple photosynthetic bacterium Rhodobacter sphaeroides, the LH complexes and RCs are only synthesized when the oxygen tension is below a critical value (11,12). Then if cells are grown at high light intensities, the PSU is dominated by LH1/RC core complexes (13,14). If the light intensity is reduced, the size of the PSU is increased by the addition of LH2 complexes (8).…”

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confidence: 99%

Tracking energy transfer between light harvesting complex 2 and 1 in photosynthetic membranes grown under high and low illumination

Lüer

Moulisová

Henry

et al. 2012

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

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Energy transfer (ET) between B850 and B875 molecules in light harvesting complexes LH2 and LH1/RC (reaction center) complexes has been investigated in membranes of Rhodopseudomonas palustris grown under high-and low-light conditions. In these bacteria, illumination intensity during growth strongly affects the type of LH2 complexes synthesized, their optical spectra, and their amount of energetic disorder. We used a specially built femtosecond spectrometer, combining tunable narrowband pump with broadband white-light probe pulses, together with an analytical method based on derivative spectroscopy for disentangling the congested transient absorption spectra of LH1 and LH2 complexes. This procedure allows real-time tracking of the forward (LH2 → LH1) and backward (LH2 ← LH1) ET processes and unambiguous determination of the corresponding rate constants. In low-light grown samples, we measured lower ET rates in both directions with respect to high-light ones, which is explained by reduced spectral overlap between B850 and B875 due to partial redistribution of oscillator strength into a higher energetic exciton transition. We find that the low-light adaptation in R. palustris leads to a reduced elementary backward ET rate, in accordance with the low probability of two simultaneous excitations reaching the same LH1/RC complex under weak illumination. Our study suggests that backward ET is not just an inevitable consequence of vectorial ET with small energetic offsets, but is in fact actively managed by photosynthetic bacteria.bacteriochlorophylls | ultrafast spectroscopy

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“…Differential expression of multiple different puc operons results in a modification of the spectral properties of the LH2 complexes present. The genes expressed under very low light conditions often give rise to light-harvesting complexes with having near-IR absorption maxima at 800 nm and 820 nm (21,22) as opposed to the more standard complexes with absorption maxima at 800 nm and 850 nm. The molecular origin of the spectral difference between B800-820 and B800-850 type LH2 is well understood.…”

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confidence: 99%

Antenna mixing in photosynthetic membranes from Phaeospirillum molischianum

Mascle-Allemand¹,

Duquesne²,

Lebrun

et al. 2010

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

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We have investigated the adaptation of the light-harvesting system of the photosynthetic bacterium Phaeospirillum molischianum (DSM120) to very low light conditions. This strain is able to respond to changing light conditions by differentially modulating the expression of a family of puc operons that encode for peripheral light-harvesting complex (LH2) polypeptides. This modulation can result in a complete shift between the production of LH2 complexes absorbing maximally near 850 nm to those absorbing near 820 nm. In contradiction to prevailing wisdom, analysis of the LH2 rings found in the photosynthetic membranes during light adaptation are shown to have intermediate spectral and electrostatic properties. By chemical cross-linking and mass-spectrometry we show that individual LH2 rings and subunits can contain a mixture of polypeptides derived from the different operons. These observations show that polypeptide synthesis and insertion into the membrane are not strongly coupled to LH2 assembly. We show that the light-harvesting complexes resulting from this mixing could be important in maintaining photosynthetic efficiency during adaptation.chromatic adaptation | membrane protein | photosynthetic bacteria | Rhodospirillum molischianum P hotosynthetic bacteria are able to efficiently convert incident light into chemical potential energy via a light-driven cyclic electron transfer pathway (1). This process depends on the efficient absorption of incident light energy and the transfer of this energy to the reaction center. Measurements of the quantum efficiency of the light-harvesting apparatus indicate that very little energy is lost during the migration of the exciton from the point of initial absorption to the reaction center (1). The light-harvesting system of many bacteria contains two different pigment-protein complexes. The core complex contains one or two reaction centers in close association with a light-harvesting system (LH1) and a smaller peripheral complex (LH2) that transfers the absorbed excitation energy to the core complex. Both types of light-harvesting complex, LH1 and LH2, are constructed from oligomers of a similar basic subunit containing 2 polypeptides (α and β) with associated bacteriochlorophyll and carotenoid pigments. Their structures are known from x-ray crystallography (2-4), electron crystallography (5), and more recently from atomic force microscopy (6-11).The LH2 complexes are circular oligomers of typically 9 αβ subunits (3), in which 18 long wavelength-absorbing bacteriochlorophyll molecules are sandwiched between the inner ring of α-polypeptides and an outer-ring of β-polypeptides. A second series of 9 bacteriochlorohpyll molecules, closer to the cytoplasmic membrane surface, occupies gaps between the β-polypeptides. This general architecture is slightly variable, with in particular the number of monomeric units forming the circular architecture depending on the species and environmental conditions (2,7,12,13). In the species studied in this work, Phaeospirillum (Ph.) molischianum...

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Isolation and characterisation of the different B800–850 light-harvesting complexes from low- and high-light grown cells of Rhodopseudomonas palustris, strain 2.1.6

Cited by 55 publications

References 13 publications

Structural determination of dihydro‐ and tetrahydrogeranylgeranyl groups at the 17‐propionate of bacteriochlorophylls‐a

Structural determination of dihydro‐ and tetrahydrogeranylgeranyl groups at the 17‐propionate of bacteriochlorophylls‐a

Tracking energy transfer between light harvesting complex 2 and 1 in photosynthetic membranes grown under high and low illumination

Antenna mixing in photosynthetic membranes from Phaeospirillum molischianum

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