The Light-Harvesting Apparatus in Purple Photosynthetic Bacteria: Introduction to a Quantum Biological Device

Strümpfer, Johan; Hsin, Jen; Sener, Melih; Chandler, Danielle E.; Schulten, Klaus

doi:10.1142/9789814343466_0002

Cited by 4 publications

(5 citation statements)

References 72 publications

(162 reference statements)

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“…In the purple bacterium Rhodobacter (Rba.) sphaeroides the basic photosynthetic unit is the chromatophore ( Cogdell et al, 2006 ; Strümpfer et al, 2011 ; Cartron et al, 2014 ), a 50–70 nm diameter vesicle, as shown in Figure 1 , formed through invagination of the intracytoplasmic membrane ( Tucker et al, 2010 ; Gubellini et al, 2007 ) and comprising over a hundred protein complexes ( Jackson et al, 2012 ; Woronowicz and Niederman, 2010 ; Woronowicz et al, 2013 ). The proteins that constitute the chromatophore are primarily the light harvesting (LH) complexes, photosynthetic reaction centers (RCs), cyt

complexes, and ATP synthases, which cooperate to harvest light energy for photophosphorylation.…”

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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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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complexes, and ATP synthases, which cooperate to harvest light energy for photophosphorylation.…”

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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“…The focus of this review is to explain how this quantum coherence increases efficiency 41 and architectural flexibility 8 in the light harvesting system of a fundamental photosynthetic life form, namely purple bacteria. 1,2,42 …”

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confidence: 99%

“…The quantum coherence that we discuss in this Perspective arises through strong coupling between chlorophyll molecules making close contact with each other in the proteins of the photosynthetic apparatus. The focus of our review is to explain how this quantum coherence increases efficiency and architectural flexibility in the light-harvesting system of a fundamental photosynthetic life form, namely, purple bacteria. ,, …”

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confidence: 99%

How Quantum Coherence Assists Photosynthetic Light-Harvesting

Strümpfer

Sener

Schulten

2012

J. Phys. Chem. Lett.

180

261

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This perspective examines how hundreds of pigment molecules in purple bacteria cooperate through quantum coherence to achieve remarkable light harvesting efficiency. Quantum coherent sharing of excitation, which modifies excited state energy levels and combines transition dipole moments, enables rapid transfer of excitation over large distances. Purple bacteria exploit the resulting excitation transfer to engage many antenna proteins in light harvesting, thereby increasing the rate of photon absorption and energy conversion. We highlight here how quantum coherence comes about and plays a key role in the photosynthetic apparatus of purple bacteria.

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“…The simulation of chromatophore components shown in the movies has been the subject of nearly 40 publications by the senior author over the last three decades [6] (see Table 1), driving development efforts for simulation and visualization software packages NAMD [12] and VMD [7]. The chromatophore model shown in Fig.…”

Section: Computational Challengesmentioning

confidence: 99%

“…In the case of purple photosynthetic bacteria, the photosynthetic apparatus is the so-called chromatophore, now structurally known at atomic detail [5, 4]; the chromatophore is a spherical membrane of 50 nm inner diameter, comprising over a hundred proteins and ~3,000 bacteriochlorophylls for photon absorption [6] (see Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Atomic detail visualization of photosynthetic membranes with GPU-accelerated ray tracing

et al. 2016

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The cellular process responsible for providing energy for most life on Earth, namely photosynthetic light-harvesting, requires the cooperation of hundreds of proteins across an organelle, involving length and time scales spanning several orders of magnitude over quantum and classical regimes. Simulation and visualization of this fundamental energy conversion process pose many unique methodological and computational challenges. We present, in two accompanying movies, light-harvesting in the photosynthetic apparatus found in purple bacteria, the so-called chromatophore. The movies are the culmination of three decades of modeling efforts, featuring the collaboration of theoretical, experimental, and computational scientists. We describe the techniques that were used to build, simulate, analyze, and visualize the structures shown in the movies, and we highlight cases where scientific needs spurred the development of new parallel algorithms that efficiently harness GPU accelerators and petascale computers.

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The Light-Harvesting Apparatus in Purple Photosynthetic Bacteria: Introduction to a Quantum Biological Device

Cited by 4 publications

References 72 publications

Overall energy conversion efficiency of a photosynthetic vesicle

Overall energy conversion efficiency of a photosynthetic vesicle

How Quantum Coherence Assists Photosynthetic Light-Harvesting

Atomic detail visualization of photosynthetic membranes with GPU-accelerated ray tracing

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