Crystal structure of the bacteriochlorophyll a protein from Chlorobium tepidum 1 1Edited by R. Huber

Li, Yi Fen; Zhou, Wenli; Blankenship, Robert E.; Allen, James P.

doi:10.1006/jmbi.1997.1189

Cited by 198 publications

(217 citation statements)

References 64 publications

Supporting

Mentioning

215

Contrasting

Order By: Relevance

“…The interaction between the flat surface of the FMO trimer and the RC, shown by the STEM image (26), is not as strong as proposed on the basis of protein hydrophobicity, suggesting that the FMO is probably partially buried in the CM (12). On the chlorosome side, the detailed interaction between the FMO and the CsmA protein is not clear, although surface plasmon resonance (27) and cross-linking data (28) suggest that FMO protein directly interacts with the CsmA protein and is probably partially buried in the CsmA layer (28).…”

mentioning

confidence: 74%

See 1 more Smart Citation

Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting

Wen¹,

Zhang

Gross

et al. 2009

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

Self Cite

195

228

View full text Add to dashboard Cite

The high excitation energy-transfer efficiency demanded in photosynthetic organisms relies on the optimal pigment-protein binding orientation in the individual protein complexes and also on the overall architecture of the photosystem. In green sulfur bacteria, the membrane-attached Fenna-Matthews-Olson (FMO) antenna protein functions as a ''wire'' to connect the large peripheral chlorosome antenna complex with the reaction center (RC), which is embedded in the cytoplasmic membrane (CM). Energy collected by the chlorosome is funneled through the FMO to the RC. Although there has been considerable effort to understand the relationships between structure and function of the individual isolated complexes, the specific architecture for in vivo interactions of the FMO protein, the CM, and the chlorosome, ensuring highly efficient energy transfer, is still not established experimentally. Here, we describe a mass spectrometrybased method that probes solvent-exposed surfaces of the FMO by labeling solvent-exposed aspartic and glutamic acid residues. The locations and extents of labeling of FMO on the native membrane in comparison with it alone and on a chlorosome-depleted membrane reveal the orientation. The large differences in the modification of certain peptides show that the Bchl a #3 side of the FMO trimer interacts with the CM, which is consistent with recent theoretical predictions. Moreover, the results also provide direct experimental evidence to confirm the overall architecture of the photosystem from Chlorobaculum tepidum (C. tepidum) and give information on the packing of the FMO protein in its native environment.chemical labeling ͉ energy transfer ͉ FMO protein ͉ mass spectrometry ͉ protein footprinting P hotosynthesis is a fundamental biological process that harvests solar energy to power life on Earth (1). A diverse family of pigment-protein complexes and elegant architectures accomplish the necessary light-harvesting and energy-storage processes (2-5). In photosynthetic green sulfur bacteria, light absorbed by a large antenna complex known as a chlorosome (6-8) is transferred through a protein called Fenna-Matthews-Olson (FMO) (9) to the reaction center, which is embedded in the cytoplasmic membrane (CM). Together, they form a funnel-like architecture to facilitate energy transfer. The specific orientation of the critical linker, the FMO protein, however is unknown (Fig. 1A).The structure of the FMO protein was the first (bacterio)chlorophyll binding protein to be determined by X-ray crystallography. Structures of this protein from 2 species, Prosthecochloris aestuarii 2K (10, 11) and Chlorobaculum tepidum (12) are now available, and they show strong structural and spectral similarities. The FMO protein consists of 3 identical subunits of mass 40 kDa related by a 3-fold axis of symmetry. The 3 monomers form a disc with a C3 symmetry axis perpendicular to the disc plane (Fig. 1B). There are 7 BChl a molecules in a monomer, although an eighth pigment has been resolved in newly solved structures (13,14). Eac...

show abstract

mentioning

confidence: 74%

“…Structures of this protein from 2 species, Prosthecochloris aestuarii 2K (10,11) and Chlorobaculum tepidum (12) are now available, and they show strong structural and spectral similarities. The FMO protein consists of 3 identical subunits of mass 40 kDa related by a 3-fold axis of symmetry.…”

mentioning

confidence: 99%

Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting

Wen¹,

Zhang

Gross

et al. 2009

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

Self Cite

195

228

View full text Add to dashboard Cite

show abstract

“…Such a quenching mechanism of a light-excited chromophore has been well demonstrated in riboflavin-binding proteins, in which electron exchange efficiently occurs with two nearby aromatic residues (Tyr-75 and Trp-156) that sandwich riboflavin in a hydrophobic cleft (36). The possible involvement of aromatic residues in fluorescence quenching of bacteriochlorophyll and Chl molecules is also discussed in (29,37,38).…”

mentioning

confidence: 91%

Structural Mechanism and Photoprotective Function of Water-soluble Chlorophyll-binding Protein

Horigome

Satoh²,

Itoh

et al. 2007

Journal of Biological Chemistry

108

216

View full text Add to dashboard Cite

A water-soluble chlorophyll-binding protein (WSCP) is the single known instance of a putative chlorophyll (Chl) carrier in green plants. Recently the photoprotective function of WSCP has been demonstrated by EPR measurements; the light-induced singlet-oxygen formation of Chl in the WSCP tetramer is about four times lower than that of unbound Chl. This paper describes the crystal structure of the WSCP-Chl complex purified from leaves of Lepidium virginicum (Virginia pepperweed) to clarify the mechanism of its photoprotective function. The WSCP-Chl complex is a homotetramer comprising four protein chains of 180 amino acids and four Chl molecules. At the center of the complex one hydrophobic cavity is formed in which all of the four Chl molecules are tightly packed and isolated from bulk solvent. With reference to the novel Chl-binding mode, we propose that the photoprotection mechanism may be based on the inhibition of physical contact between the Chl molecules and molecular oxygen.Water-soluble chlorophyll-binding proteins (WSCPs), 4 which form a complex with chlorophyll (Chl), have been isolated from Amaranthaceae, Chenopodiaceae, and Polygonaceae (class-I) and from Brassicaceae (class-II). The two WSCP classes differ in that the protein-Chl complexes of the former change their absorption spectra upon illumination, whereas those of the latter show no photoconversion of their absorption behavior (2). The amino acid sequence of class-I WSCP shows no similarity to that of class-II WSCP.The class-II WSCPs (hereafter referred to as "WSCPs") are water-soluble proteins of ϳ20 kDa, which form a tetrameric assembly upon binding Chl molecules with a Chl-to-protein ratio of one or less, and exhibit high thermal and photostability (1, 3). The physiological function of WSCPs is still not known. Although WSCPs have a sequence similarity of ϳ30% with Künitz-type proteinase inhibitors, no significant protease inhibitor activity of WSCPs has yet been identified (4 -6). The low Chl content per protein makes it unlikely that WSCPs are involved in the light reaction of photosynthesis. Meanwhile, it has been speculated (7, 8) that WSCP acts as a scavenger of free Chl, by transporting it from the thylakoid membrane to the chloroplast envelope, where Chlase, the enzyme that initiates the Chl catabolism, is thought to reside (9).An in vitro binding assay with the recombinant apo-WSCP cloned from cauliflower (Brassica oleralcea var. Botrys) and Chl or its derivatives showed that the central Mg 2ϩ ion and the phytyl tail of Chl were essential for protein-pigment binding and tetrameric assembly, respectively (1). Furthermore, the recombinant apo-WSCP was able to remove Chl from the thylakoid membrane in vitro and organize the tetrameric WSCPChl complex (3). The absorption spectrum of the reconstituted complex is very similar to that of the native WSCP-Chl complex purified from fresh leaves (1, 3).The WSCP-Chl complex retains its fresh green color under dim light for months, enough for a long term crystallization experiment. Free Chl, on t...

show abstract

“…Specifically, we adopt a network-based view of photosynthetic EET systems and focus on investigating quantum transport dynamics in a prototypical PPC, the FMO complex. 9,[33][34][35][36][37][38] In green sulfur bacteria (GSB) such as C. tepidum, 39 FMO trimers facilitate EET from the chlorosome to the membranebound RC; in this process, each FMO monomer acts as an independent "molecular wiring circuit" connecting the light-harvesting antenna complex (energy source) to the RC (energy sink) ( Fig. 1(a)).…”

Section: Introductionmentioning

confidence: 99%

Robustness, efficiency, and optimality in the Fenna-Matthews-Olson photosynthetic pigment-protein complex

Baker

Habershon

2015

The Journal of Chemical Physics

View full text Add to dashboard Cite

Pigment-protein complexes (PPCs) play a central role in facilitating excitation energy transfer (EET) from light-harvesting antenna complexes to reaction centres in photosynthetic systems; understanding molecular organisation in these biological networks is key to developing better artificial lightharvesting systems. In this article, we combine quantum-mechanical simulations and a network-based picture of transport to investigate how chromophore organization and protein environment in PPCs impacts on EET efficiency and robustness. In a prototypical PPC model, the Fenna-Matthews-Olson (FMO) complex, we consider the impact on EET efficiency of both disrupting the chromophore network and changing the influence of (local and global) environmental dephasing. Surprisingly, we find a large degree of resilience to changes in both chromophore network and protein environmental dephasing, the extent of which is greater than previously observed; for example, FMO maintains EET when 50% of the constituent chromophores are removed, or when environmental dephasing fluctuations vary over two orders-of-magnitude relative to the in vivo system. We also highlight the fact that the influence of local dephasing can be strongly dependent on the characteristics of the EET network and the initial excitation; for example, initial excitations resulting in rapid coherent decay are generally insensitive to the environment, whereas the incoherent population decay observed following excitation at weakly coupled chromophores demonstrates a more pronounced dependence on dephasing rate as a result of the greater possibility of local exciton trapping. Finally, we show that the FMO electronic Hamiltonian is not particularly optimised for EET; instead, it is just one of many possible chromophore organisations which demonstrate a good level of EET transport efficiency following excitation at different chromophores. Overall, these robustness and efficiency characteristics are attributed to the highly connected nature of the chromophore network and the presence of multiple EET pathways, features which might easily be built into artificial photosynthetic systems. C 2015 AIP Publishing LLC. [http://dx

show abstract

Crystal structure of the bacteriochlorophyll a protein from Chlorobium tepidum 1 1Edited by R. Huber

Cited by 198 publications

References 64 publications

Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting

Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting

Structural Mechanism and Photoprotective Function of Water-soluble Chlorophyll-binding Protein

Robustness, efficiency, and optimality in the Fenna-Matthews-Olson photosynthetic pigment-protein complex

Contact Info

Product

Resources

About