The crystal structure of the light-harvesting complex II (B800–850) from Rhodospirillum molischianum

Koepke, Juergen; Hu, Xiche; Muenke, Cornelia; Schulten, Klaus; Michel, Hartmut

doi:10.1016/s0969-2126(96)00063-9

Cited by 1,044 publications

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“…The primary components of chromatophore vesicles in purple bacteria, as depicted in Figure 1, are, in order of energy utililization (Cogdell et al, 2006,Cartron et al, 2014: (i) light harvesting complex 2 (LH2) (Koepke et al, 1996;Papiz et al, 2003); (ii) light harvesting complex 1 (LH1 Sener et al, 2009]); (iii) RC (Jamieson et al, 2002;Strümpfer and Schulten, 2012a); (iv) cytbc 1 (Crofts, 2004;Crofts et al, 2006); and (v) ATP synthase (Feniouk and Junge, 2009;Hakobyan et al, 2012). RC-LH1 complexes typically form dimeric RC-LH1-PufX complexes facilitated by the polypeptide PufX Sener et al, 2009), although monomeric complexes are also found in membranes from photosynthetically grown cells at a ratio of approximately 10% .…”

Section: Supramolecular Organization Of a Chromatophore Vesicle Adaptmentioning

confidence: 99%

“…The proteins that constitute the chromatophore are primarily the light harvesting (LH) complexes, photosynthetic reaction centers (RCs), cytbc 1 complexes, and ATP synthases, which cooperate to harvest light energy for photophosphorylation. The architecture of the chromatophore, reported in (Ş ener et al, 2007, 2010Cartron et al, 2014), has been determined by combining atomic force microscopy (AFM) (Bahatyrova et al, 2004;Olsen et al, 2008), cryo-electron microscopy (cryo-EM) (Qian et al, 2005;Cartron et al, 2014), crystallography (Koepke et al, 1996;McDermott et al, 1995;Papiz et al, 2003;Jamieson et al, 2002), optical spectroscopy Sener et al, 2010), mass spectroscopy (Cartron et al, 2014), and proteomics (Jackson et al, 2012;Woronowicz and Niederman, 2010;Woronowicz et al, 2013) data. The composition of the chromatophore depends on growth conditions such as light intensity (Adams and Hunter, 2012;Woronowicz et al, 2011bWoronowicz et al, , 2011a) and can also be influenced by mutations Hsin et al, 2010b).…”

Section: Introductionmentioning

confidence: 99%

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Overall energy conversion efficiency of a photosynthetic vesicle

Sener

Strümpfer

Singharoy

et al. 2016

eLife

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The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-lightadapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc 1 complex (cytbc 1 ) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

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Section: Supramolecular Organization Of a Chromatophore Vesicle Adaptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Overall energy conversion efficiency of a photosynthetic vesicle

Sener

Strümpfer

Singharoy

et al. 2016

eLife

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174

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“…However, electron microscopy on Rb. sphaeroides LH2 complexes suggests a hexameric structure indicating a (R ) 6 organization. 15 Rsp.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Light-Harvesting Antennas of Photosynthetic Purple Bacteria by Stark Spectroscopy. 2. LH2 Complexes: Influence of the Protein Environment

et al. 1997

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We have performed low-temperature Stark spectroscopy on a variety of different LH2 complexes from four photosynthetic bacteria, with the aim of characterizing the electric field response of the B800 and B850 absorption properties as a function of the protein environment. The following LH2 complexes were investigated: B800-850 and B800-820 of Rhodopseudomonas (Rps) acidophila; B800-850, B800-840 (RTyr +13 fPhe), and B800-826 (RTyr +13 fPhe, RTyr +14 fLeu) of Rhodobacter (Rb.) sphaeroides; B800-850 and B800-830 (obtained at high LDAO) of Ectothiorhodospira sp.; and B800-850 of Rhodospirillum (Rsp.) molischianum. For all these cases the spectral blue shift of B850 has been assigned to the loss hydrogenbonding interaction with the acetyl carbonyl of bacteriochlorophyll a. |∆µ| values for the 850 nm bands as well as for the blue-shifted bands are all on the order of 3-4.5 D/f. The loss of hydrogen-bonding interactions has only small effects on |∆µ| in these complexes. The values of the difference polarizability, Tr(∆r), are large (600-1400 Å 3 /f 2 ). The results are discussed in terms of crystal-structure-based models for LH2, in which pigment-pigment and pigment-protein interactions are considered; strong pigment-pigment interactions were found to be especially important. The values of |∆µ| for the 800 nm band are small, 1.0-1.5 D/f for LH2 complexes from Rb. sphaeroides and Rps. acidophila. However, in Rsp. molischianum and Ectothiorhodospira sp. |∆µ| values are much larger, of the order of 3 D/f. The difference in the B800 band is assigned to the difference in orientation of the B800 pigments in Rsp. molischianum and Ectothiorhodospira sp., as compared to the Rps. acidophila and Rb. sphaeroides. Due to the difference in orientation, the interactions of the Bchl a with the surrounding protein and neighboring carotenoid pigments are also not identical.

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“…Expectedly, this fraction is zero for all fluences at the repetition rate of 81 kHz as the time delay between two successive pulses of about 12 μs exceeds the lifetime of the triplet state by at least a factor of 5. For the other three repetition rates the fraction of RC-LH1 complexes that carry 3 Car* states on the LH1 ring increases by several orders of magnitude with increasing fluence; see Figure 8A. Representing the same data as a function of the repetition rate for the cw equivalent excitation intensities, Figure 8B, reveals for all intensities an increase of the triplet population for rising the repetition rate from 810 kHz to 8.1 MHz, which levels off for a further increase of the repetition to 81 MHz.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

The Open, the Closed, and the Empty: Time-Resolved Fluorescence Spectroscopy and Computational Analysis of RC-LH1 Complexes from Rhodopseudomonas palustris

et al. 2015

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ABSTRACT:We studied the time-resolved fluorescence of isolated RC-LH1 complexes from Rhodopseudomonas palustris as a function of the photon fluence and the repetition rate of the excitation laser. Both parameters were varied systematically over 3 orders of magnitude. On the basis of a microstate description we developed a quantitative model for RC-LH1 and obtained very good agreement between experiments and elaborate simulations based on a global master equation approach. The model allows us to predict the relative population of RC-LH1 complexes with the special pair in the neutral state or in the oxidized state P + and those complexes that lack a reaction center. ■ INTRODUCTIONPhotosynthetic purple bacteria have evolved a wonderful modular principle for the light-harvesting (LH) apparatus that captures the solar radiation. These modules consist of pairs of hydrophobic, low molecular weight polypeptides that noncovalently bind a small number of bacteriochlorophyll (Bchl a) and carotenoid (Car) molecules and that self-assemble to produce the native pigment−protein complexes. 1−6 Most purple bacteria have two main types of complexes, the core complex, RC-LH1, and the peripheral complex, LH2. In the photosynthetic membrane the LH2 complexes are arranged in a two-dimensional network around the perimeter of the RC-LH1 complexes and the light energy absorbed by LH2 is transferred via LH1 to the reaction center (RC) where it is used to separate charge across the membrane. 7 For many years, high-resolution structural information has been available for the RC, 8−11 and the peripheral light-harvesting complexes 1−3 for a couple of species, whereas the first higher-resolution X-ray structure for a RC-LH1 complex has been determined only recently. 6 The current view is that there are at least two distinct classes of RC-LH1 complexes: Those that are monomeric, i.e., consisting of one RC surrounded by one LH1 complex, and those that are dimeric. 12,13 For RC-LH1 from Rps. palustris exists a lowresolution X-ray structure. 4 Accordingly, the RC is enclosed by an overall elliptically shaped LH1 consisting of 15 αβ-subunits that feature a gap, which is also consistent with data from optical single-molecule experiments. 14,15 Each subunit accommodates two light harvesting BChl a molecules giving rise to an absorption band at 875 nm. The reaction center complex accommodates a BChl a dimer (special pair, primary donor, P), two accessory BChl a molecules (B A , B B ), two bacteriopheophytin a (BPheo a) molecules (H A , H B ), and two ubiquinones (Q A , Q B ) bound to two protein subunits denoted L and M. The cofactors are arranged in two nearly identical branches, called A and B, which share the primary donor, P. 9,11,16,17 In particular the RC from Rhodobacter (Rb.) sphaeroides has served as a cornerstone for elucidating structure−function relationships employing a large variety of spin resonance 18−23 and optical spectroscopies. 24−31 From these studies it is well established that in the RC the absorbed photon-energy is used to dri...

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The crystal structure of the light-harvesting complex II (B800–850) from Rhodospirillum molischianum

Cited by 1,044 publications

References 69 publications

Overall energy conversion efficiency of a photosynthetic vesicle

Overall energy conversion efficiency of a photosynthetic vesicle

Characterization of the Light-Harvesting Antennas of Photosynthetic Purple Bacteria by Stark Spectroscopy. 2. LH2 Complexes: Influence of the Protein Environment

The Open, the Closed, and the Empty: Time-Resolved Fluorescence Spectroscopy and Computational Analysis of RC-LH1 Complexes from Rhodopseudomonas palustris

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