scholarly journals Interaction of Triton X-100 with the pigment-protein complexes of photosynthetic membranes

1985 ◽  
Vol 229 (1) ◽  
pp. 31-37 ◽  
Author(s):  
D J Murphy ◽  
R T Prinsley
Keyword(s):  
Protein Complexes ◽  
Fluorescence Emission ◽  
Critical Micellar Concentration ◽  
Photosynthetic Membrane ◽  
Photosynthetic Membranes ◽  
Ionic Detergent ◽  
Pigment Protein Complexes ◽  
Membrane Components ◽  
Triton X ◽  
Detergent Effect

The interaction of the non-ionic detergent Triton X-100 with photosynthetic membrane components of Pisum sativum (pea) is described. The detergent affected both the wavelength and the intensity of the 77K fluorescence-emission peaks of both Photosystem I and Photosystem II preparations, in addition to the effects on whole thylakoids recently described by Murphy & Woodrow [(1984) Biochem. J. 224, 989-993]. Below its critical micellar concentration, Triton X-100 had no effect on 77K fluorescence emissions even after prolonged incubations of up to 30 min. Above the critical micellar concentration of about 0.16 mg X ml-1, Triton X-100 caused a dramatic increase in the intensity of the 680 nm emission. The intensity of the 680 nm fluorescence emission continued to increase as more Triton X-100 was added, until limiting concentrations of detergent were reached. These limiting concentrations were proportional to the amount of membrane present and generally occurred at Triton X-100/chlorophyll (w/w) ratios of 100-200:1. In all cases the detergent effect was seen within 10 min, and is often considerably faster, with longer detergent treatments causing no further effects. The data are discussed in terms of a three-stage mechanism for detergent solubilization of membrane components.

scholarly journals The effects of Triton X-100 and n-octyl β-d-glucopyranoside on energy transfer in photosynthetic membranes

1984 ◽  
Vol 224 (3) ◽  
pp. 989-993 ◽  
Author(s):  
D J Murphy ◽  
I E Woodrow
Keyword(s):  
Energy Transfer ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Emission Peak ◽  
Wavelength Shift ◽  
Emission Characteristics ◽  
Ionic Detergents ◽  
Reversible Dissociation ◽  
Pigment Protein Complexes ◽  
Triton X

The effects of the non-ionic detergents Triton X-100 and n-octyl beta-D-glucopyranoside on energy transfer between pigment-protein complexes of Pisum sativum thylakoids were investigated. This was done by monitoring the 77K fluorescence-emission characteristics of stacked and unstacked thylakoids exposed to a range of detergent concentrations. At sub-critical micellar concentrations, the detergents had little effect, whereas above these concentrations they caused increases of up to 20-fold in short-wavelength fluorescence intensity and a shift in its maximum wavelength from 685 to 680 nm. Fluorescence-emission intensities at 695 and 735 nm were relatively unaffected by detergent treatments, although Triton X-100 caused a wavelength shift in the emission peak from 735 to 728 nm. The results are discussed in terms of reversible dissociation of pigment-protein complexes induced by mild detergent solubilization and the consequent cessation of inter-complex energy transfer.

scholarly journals A photosynthetic antenna complex foregoes unity carotenoid-to-bacteriochlorophyll energy transfer efficiency to ensure photoprotection

2020 ◽  
Vol 117 (12) ◽  
pp. 6502-6508 ◽  
Author(s):  
Dariusz M. Niedzwiedzki ◽  
David J. K. Swainsbury ◽  
Daniel P. Canniffe ◽  
C. Neil Hunter ◽  
Andrew Hitchcock
Keyword(s):  
Energy Transfer ◽  
Transient Absorption ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Energy Transfer Efficiency ◽  
Transfer Efficiency ◽  
Light Harvesting Complexes ◽  
Antenna Complex ◽  
Pigment Protein Complexes

Carotenoids play a number of important roles in photosynthesis, primarily providing light-harvesting and photoprotective energy dissipation functions within pigment–protein complexes. The carbon–carbon double bond (C=C) conjugation length of carotenoids (N), generally between 9 and 15, determines the carotenoid-to-(bacterio)chlorophyll [(B)Chl] energy transfer efficiency. Here we purified and spectroscopically characterized light-harvesting complex 2 (LH2) fromRhodobacter sphaeroidescontaining theN= 7 carotenoid zeta (ζ)-carotene, not previously incorporated within a natural antenna complex. Transient absorption and time-resolved fluorescence show that, relative to the lifetime of the S1state of ζ-carotene in solvent, the lifetime decreases ∼250-fold when ζ-carotene is incorporated within LH2, due to transfer of excitation energy to the B800 and B850 BChlsa. These measurements show that energy transfer proceeds with an efficiency of ∼100%, primarily via the S1→ Qxroute because the S1→ S0fluorescence emission of ζ-carotene overlaps almost perfectly with the Qxabsorption band of the BChls. However, transient absorption measurements performed on microsecond timescales reveal that, unlike the nativeN≥ 9 carotenoids normally utilized in light-harvesting complexes, ζ-carotene does not quench excited triplet states of BChla, likely due to elevation of the ζ-carotene triplet energy state above that of BChla. These findings provide insights into the coevolution of photosynthetic pigments and pigment–protein complexes. We propose that theN≥ 9 carotenoids found in light-harvesting antenna complexes represent a vital compromise that retains an acceptable level of energy transfer from carotenoids to (B)Chls while allowing acquisition of a new, essential function, namely, photoprotective quenching of harmful (B)Chl triplets.

scholarly journals Pigment-Protein Complexes from the Photosynthetic Membrane of the Cyanobacterium Synechocystis sp. PCC 6803

1995 ◽  
Vol 234 (2) ◽  
pp. 459-465 ◽  
Author(s):  
Roberto Barbato ◽  
Patrizia Polverino Laureto ◽  
Fernanda Rigoni ◽  
Elena Martini ◽  
Giorgio M. Giacometti
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Membrane ◽  
Pigment Protein Complexes ◽  
Synechocystis Sp ◽  
Pcc 6803

scholarly journals Proteomic Characterization of the Rhodobacter sphaeroides 2.4.1 Photosynthetic Membrane: Identification of New Proteins

2007 ◽  
Vol 189 (20) ◽  
pp. 7464-7474 ◽  
Author(s):  
Xiaohua Zeng ◽  
Jung Hyeob Roh ◽  
Stephen J. Callister ◽  
Christine L. Tavano ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Rhodobacter Sphaeroides ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Energy Utilization ◽  
Alkane Hydroxylase ◽  
Photosynthetic Membrane ◽  
Intracytoplasmic Membrane ◽  
Light Harvesting Complexes ◽  
Pigment Protein Complexes

ABSTRACT The Rhodobacter sphaeroides intracytoplasmic membrane (ICM) is an inducible membrane that is dedicated to the major events of bacterial photosynthesis, including harvesting light energy, separating primary charges, and transporting electrons. In this study, multichromatographic methods coupled with Fourier transform ion cyclotron resonance mass spectrometry, combined with subcellular fractionation, was used to test the hypothesis that the photosynthetic membrane of R. sphaeroides 2.4.1 contains a significant number of heretofore unidentified proteins in addition to the integral membrane pigment-protein complexes, including light-harvesting complexes 1 and 2, the photochemical reaction center, and the cytochrome bc 1 complex described previously. Purified ICM vesicles are shown to be enriched in several abundant, newly identified membrane proteins, including a protein of unknown function (AffyChip designation RSP1760) and a possible alkane hydroxylase (RSP1467). When the genes encoding these proteins are mutated, specific photosynthetic phenotypes are noted, illustrating the potential new insights into solar energy utilization to be gained by this proteomic blueprint of the ICM. In addition, proteins necessary for other cellular functions, such as ATP synthesis, respiration, solute transport, protein translocation, and other physiological processes, were also identified to be in association with the ICM. This study is the first to provide a more global view of the protein composition of a photosynthetic membrane from any source. This protein blueprint also provides insights into potential mechanisms for the assembly of the pigment-protein complexes of the photosynthetic apparatus, the formation of the lipid bilayer that houses these integral membrane proteins, and the possible functional interactions of ICM proteins with activities that reside in domains outside this specialized bioenergetic membrane.

Associations of Pigment-Protein Complexes in Phospholipid Enriched Bacterial Photosynthetic Membranes

1989 ◽  
pp. 227-231 ◽  
Author(s):  
W. H. J. Westerhuis ◽  
M. Vos ◽  
R. J. van Dorssen ◽  
R. van Grondelle ◽  
J. Amesz ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Membranes ◽  
Pigment Protein Complexes

Herbicides which Interfere with the Biosynthesis of Carotenoids and Their Effect on Pigment Excitation, Chlorophyll Fluorescence and Pigment Composition of the Thylakoid Membrane

1984 ◽  
Vol 39 (5) ◽  
pp. 455-458 ◽  
Author(s):  
K. H. Grumbach
Keyword(s):  
Chlorophyll Fluorescence ◽  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Red Light ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Pigment Composition ◽  
Fluorescence Emission Spectra ◽  
Characteristic Emission ◽  
Pigment Protein Complexes

Plants grown in the presence of the herbicides assayed synthesized chlorophylls during growth at low fluence rates. Subsequent irradiation with higher fluence rates of red light induced a strong chlorosis with SAN 6706 being a much stronger herbicide than J 852 or amino-triazole. All herbicides assayed also changed the content and composition of chlorophylls, carotenoids and pigment-protein-complexes of the thylakoid membrane and therefore the pigment excitation and chlorophyll fluorescence emission spectra of the plastid. With increasing herbicide toxicity the main characteristic emission bands at 690 and 730 nm disappeared and new emission bands at 715 (J 852) and 700 nm (SAN 6706) appeared. Such “artificial” membranes with a changed pigment composition were very susceptible to light. Presented data may be taken as evidence, that the lack of photoprotective cyclic carotenoids caused by the specific action of a bleaching herbicide is the primary event that may lead to a disturbed formation of the thylakoid membrane and its destruction by light and oxygen.

Lipids in and around photosynthetic reaction centres

2005 ◽  
Vol 33 (5) ◽  
pp. 924-930 ◽  
Author(s):  
P.K. Fyfe ◽  
M.R. Jones
Keyword(s):  
Membrane Lipids ◽  
Protein Complexes ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Ps Ii ◽  
X Ray Crystallography ◽  
Structural Support ◽  
Reaction Centres ◽  
Ps I ◽  
Pigment Protein Complexes

Reaction centres are membrane-embedded pigment–protein complexes that transduce the energy of sunlight into a biologically useful form. The most heavily studied reaction centres are the PS-I (Photosystem I) and PS-II complexes from oxygenic phototrophs, and the reaction centre from purple photosynthetic bacteria. A great deal is known about the compositions and structures of these reaction centres, and the mechanism of light-activated transmembrane electron transfer, but less is known about how they interact with other components of the photosynthetic membrane, including the membrane lipids. X-ray crystallography has provided high-resolution structures for PS-I and the purple bacterial reaction centre, and revealed binding sites for a number of lipids, either embedded in the protein interior or attached to the protein surface. These lipids play a variety of roles, including the binding of cofactors and the provision of structural support. The challenges of modelling surface-associated electron density features such as lipids, detergents, small amphiphiles and ions are discussed.

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