Freeze-fracture studies on barley plastid membranes. III. Location of the light-harvesting chlorophyll-protein

Simpson, David J. W.

doi:10.1007/bf02906493

Cited by 137 publications

(123 citation statements)

References 32 publications

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“…Similar observation has been also reported earlier in a freeze-fracture electron microscopy study demonstrating decreased unit size and increased density of PSII units in the Chlorina F2 mutant (Simpson, 1979). Our data also demonstrated a higher abundance of the D1 reaction center protein of PSII in the F2 mutant compared to WT (Fig.…”

Section: Discussionsupporting

confidence: 92%

The lack of LHCII proteins modulates excitation energy partitioning and PSII charge recombination in Chlorina F2 mutant of barley

Ivanov

Król

Zeinalov

et al. 2008

Physiol Mol Biol Plants

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Analysis of the partitioning of absorbed light energy within PSII into fractions utilized by PSII photochemistry (Ø PSII ), thermally dissipated via ∆pH-and zeaxanthin-dependent energy quenching (Ø NPQ ) and constitutive non-photochemical energy losses (Ø NO ) was performed in wild type and F2 mutant of barley. The estimated energy partitioning of absorbed light to various pathways indicated that the fraction of Ø PSII was slightly higher, while the proportion of thermally dissipated energy through Ø NPQ was 38% lower in F2 mutant than in WT. In contrast, Ø NO , i.e. the fraction of absorbed light energy dissipated by additional quenching mechanism(s) was 34% higher in F2 mutant. The increased proportion of Ø NO correlated with narrowing the temperature gap (∆T M ) between S 2/3 Q B -and S 2 Q A -charge recombinations in F2 mutant as revealed by thermoluminescence measurements. We suggest that this would result in increased probability for an alternative non-radiative P680 + Q A -radical pair recombination pathway for energy dissipation within the reaction centre of PSII (reaction center quenching) and that this additional quenching mechanism might play an important role in photoprotection when the capacity for the primary, zeaxanthin-dependent non-photochemical quenching ( Research ArticleChanges in irradiance, temperature, nutrient and water availability result in imbalances between the light energy absorbed through photochemistry and energy utilization through photosynthetic electron transport coupled to carbon, nitrogen and sulphur reduction. Such an imbalance caused by changes in irradiance and/or temperature, nutrient and water availability leads to photoinhibition of photosynthesis that may result in photodamage to the D1 reaction centre polypeptide of PSII (Krause, 1988;Aro et al., 1993). The major mechanism for thermal de-excitation of excess light energy in higher plants is currently considered to be the ∆pH-and xanthophyll-cycle dependent nonphotochemical quenching (NPQ) occurring within LHCII antenna pigment bed of PSII (Demmig-Adams and Adams, 1992;Horton et al., 1996). The role of pH-and zeaxanthin-dependent shifts in the oligomerization state of LHCII in developing the rapidly relaxing energy dependent component (qE) of NPQ is well established with qE representing the major protective mechanism against photoinhibitory damage of PSII (Horton et al., 1996; Niyogi, 1999). It has been demonstrated that trimers of LHCII exhibit the optimum level of non-photochemical energy dissipation by modulating the development of the quenched state of the complex (Wentworth et al., 2004).The redox-dependent reversible phosphorylation of light-harvesting Chl a/b-binding proteins (LHCII) is the

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Section: Discussionsupporting

confidence: 92%

The lack of LHCII proteins modulates excitation energy partitioning and PSII charge recombination in Chlorina F2 mutant of barley

Ivanov

Król

Zeinalov

et al. 2008

Physiol Mol Biol Plants

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“…thylakoids showed a lateral heterogeneity of freeze-fracture particles (22). Biochemical confirmation has been hindered by the instability of isolated chlorina-f2 thylakoids, making detergent fractionation impossible.…”

Section: Preparation Of Psi and Psii By Sucrose Gradient Centrifugationmentioning

confidence: 99%

“…In fact welldeveloped grana have been described in chloroplasts of the ch/orina-J2 barley mutant, which lacks both chlorophyll b and LHCII ( 12,22), and agranal bundle sheath chloroplasts of maize have been demonstrated to contain both LHCI and LHCII (3,5). To test the role of LHCII in the regulation of structural and functional changes in thylakoid membranes, we have examined the stacking capacity of chlorina-f2 thylakoids in vitro and investigated whether membrane appressian correlates with lateral heterogeneity and the formation of functional domains, as "is the case for wild type.…”

Section: Introductionmentioning

confidence: 99%

The role of the light harvesting complex and photosystem II in thylakoid stacking in thechlorina-f2 barley mutant

Bassi

Hinz

Barbato

1985

Carlsberg Res. Commun.

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The stacking behaviour of isolated thylakoids ofthe chlorophyll b-less barley mutant chlorina-f2, which is highly deficient in the light harvesting complex (LHCII), was investigated using electron microscopy. Pre-treatment with EDTA prevented thylakoid vesiculation during de-stacking, and was essential for the induction of re-stacking, which required a higher Mg ~* concentration (25 mM) than for wild type (5 mM). The stability of re-stacked chlorina-f2 thylakoids allowed their fractionation into photosystem I and photosystem II by treatment with Triton X-100 or [~-octyl glucoside, demonstrating thylakoid lateral heterogeneity in the absence of LHCII. An Mg'*-dependent aggregation of detergent-solubilized photosystem II from chlorina-f2 occurred at the same concentration (25 mM) as the one needed for the re-stacking of isolated thylakoids. We propose that thylakoid stacking and lateral heterogeneity in chlorina-f2 is not mediated by residual LHCII polypeptides, but by a component of photosystem [I. This mechanism may also be involved in stacking of wild type thylakoids. A simple method is described for the one-step isolation from chlorina-f2 of pure photosystem I and photosystem II preparations free of their respective chlorophyll b-containing light harvesting antenna proteins.

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“…Thin section electron microscopy of a chloroplast showing the internal membranes of thylakoids, which are laterally differentiated into appressed (grana) and non-appressed (stroma) lamellae. In this chloroplast, which is from the PSI-deficient mutant viridis-zb 63, some of the stroma lamellae have collapsed (13).…”

Section: Introductionmentioning

confidence: 99%

“…Each of these functional complexes is stable in the absence of one or more of the others, as shown from studies with mutants. Thus the PSII reaction centre is assembled in the absence of LHCII, as in the barley chlorophyll b-less mutant chlorina-f2 (12), and LHCII accumulates in the absence of the PSII reaction centre, as in the mutant viridis-115 (17). Although the PSII reaction centre is stable in the absence of the oxygen evolving complex, as shown in manganese-deficient spinach (16) and the Chlamydomonas mutant BF25 (8), the oxygen evolving complex fails to assemble in the absence of PSII.…”

Section: Introductionmentioning

confidence: 99%

The structure and function of the thylakoid membrane

Simpson

Wettstein

1989

Carlsberg Res. Commun.

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Thylakoid membranes are latemUy differentiated into appressed and non-appressed regions called grana and stroma lamellae. Pure stroma lamellae isolated from wild type maize and barley leaves contain photosystem I and its light-harvesting antennae, the cytoehrome b6/fcomplex and coupling factor. Maize stroma lamellae contained only 2% of the total photosystem II polypeptides found in whole thylakoids, and most of the small amount of the photosystem II light-harvesting complex (LHCII) was associated with photosystem I. These results were consistent with the low rates of photosystem II electron transport and low levels of the high potential form of cytochrome b-559. Immune blot assays indicated that about half of the low potential form of eytochrome b-559 in stroma lamellae was antigenically distinct from that derived from the high potential form. The amount of LHCII in stroma lamellae could be increased by exposing leaves to bright white light (state 2) prior to the isolation of stroma lamellae. This LHCII caused a 15% increase in photosystem I antenna size and was different from the LHCII found in grana lamellae, since it lacked a 26 kD polypeptide possibly involved in thylakoid appression. These results demonstrate that the migration of LHCII from appressecl to non-appressed lamellae as a result of changes in the relative amounts of energy absorbed by the 2 different photosystems, also occurs in vivo.The reaction centre core of photosystem I was isolated from barley thylakoids and its molecular weight determined to be 650 kD. Attack by various proteases cleaved it into fragments of less than 5 kD, although the complex was still photoactive. However, the kinetics of photo-oxidation of P700 under light-limiting conditions were slower after proteolysis, indicating less efficient energy transfer. In a barley mutant lacking photosystem I, a chlorophyll a species absorbing at 689 nm was lacking, accounting for about 30 molecules out of every 500 in wild type thylakoids.Finally, a mutant completely lacking photosystem II activity, viridis -m, has been examined. It contained only 4% of the photosystem II-containing EFs particles found in wild type thylakoids, and lacked a chlorophyll a species absorbing at 683 nm. Immune electron microscopy revealed that the u-subunit of cytochrome b-559 and the 33 kD polypeptide of the oxygen evolving complex were correctly located in appressed thylakoids, in spite of the lack of the major photosystem II core polypeptides. A double mutant, lacking both photosystem I1 and LHCII was found to contain grana, even though its thylakoids lacked the 2 complexes normally associated with maintenance of membrane appression in vivo.

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Freeze-fracture studies on barley plastid membranes. III. Location of the light-harvesting chlorophyll-protein

Cited by 137 publications

References 32 publications

The lack of LHCII proteins modulates excitation energy partitioning and PSII charge recombination in Chlorina F2 mutant of barley

The lack of LHCII proteins modulates excitation energy partitioning and PSII charge recombination in Chlorina F2 mutant of barley

The role of the light harvesting complex and photosystem II in thylakoid stacking in thechlorina-f2 barley mutant

The structure and function of the thylakoid membrane

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