An intact light harvesting complex I antenna system is required for complete state transitions in Arabidopsis. Benson, S. L., Maheswaran, P., Ware, M. A., Hunter, C. N., Horton, P., Jansson, S., Ruban, A. V., & Johnson, M. P. Nat Plants, 1(12):15176, November, 2015. Edition: 2015/01/01
An intact light harvesting complex I antenna system is required for complete state transitions in Arabidopsis [link]Paper  doi  abstract   bibtex   
Efficient photosynthesis depends on maintaining balance between the rate of light-driven electron transport occurring in photosystem I (PSI) and photosystem II (PSII), located in the chloroplast thylakoid membranes. Balance is achieved through a process of 'state transitions' that increases energy transfer towards PSI when PSII is overexcited (state II), and towards PSII when PSI is overexcited (state I). This is achieved through redox control of the phosphorylation state of light-harvesting antenna complex II (LHCII). PSI is served by both LHCII and four light-harvesting antenna complex I (LHCI) subunits, Lhca1, 2, 3 and 4. Here we demonstrate that despite unchanged levels of LHCII phosphorylation, absence of specific Lhca subunits reduces state transitions in Arabidopsis. The severest phenotype-observed in a mutant lacking Lhca4 (DeltaLhca4)-displayed a 69% reduction compared with the wild type. Yet, surprisingly, the amounts of the PSI-LHCI-LHCII supercomplex isolated by blue native polyacrylamide gel electrophoresis (BN-PAGE) from digitonin-solubilized thylakoids were similar in the wild type and DeltaLhca mutants. Fluorescence excitation spectroscopy revealed that in the wild type this PSI-LHCI-LHCII supercomplex is supplemented by energy transfer from additional LHCII trimers in state II, whose binding is sensitive to digitonin, and which are absent in DeltaLhca4. The grana margins of the thylakoid membrane were found to be the primary site of interaction between this 'extra' LHCII and the PSI-LHCI-LHCII supercomplex in state II. The results suggest that the LHCI complexes mediate energetic interactions between LHCII and PSI in the intact membrane.
@article{benson_intact_2015,
	title = {An intact light harvesting complex {I} antenna system is required for complete state transitions in {Arabidopsis}},
	volume = {1},
	issn = {2055-0278 (Electronic) 2055-0278 (Linking)},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/27251716},
	doi = {10.1038/nplants.2015.176},
	abstract = {Efficient photosynthesis depends on maintaining balance between the rate of light-driven electron transport occurring in photosystem I (PSI) and photosystem II (PSII), located in the chloroplast thylakoid membranes. Balance is achieved through a process of 'state transitions' that increases energy transfer towards PSI when PSII is overexcited (state II), and towards PSII when PSI is overexcited (state I). This is achieved through redox control of the phosphorylation state of light-harvesting antenna complex II (LHCII). PSI is served by both LHCII and four light-harvesting antenna complex I (LHCI) subunits, Lhca1, 2, 3 and 4. Here we demonstrate that despite unchanged levels of LHCII phosphorylation, absence of specific Lhca subunits reduces state transitions in Arabidopsis. The severest phenotype-observed in a mutant lacking Lhca4 (DeltaLhca4)-displayed a 69\% reduction compared with the wild type. Yet, surprisingly, the amounts of the PSI-LHCI-LHCII supercomplex isolated by blue native polyacrylamide gel electrophoresis (BN-PAGE) from digitonin-solubilized thylakoids were similar in the wild type and DeltaLhca mutants. Fluorescence excitation spectroscopy revealed that in the wild type this PSI-LHCI-LHCII supercomplex is supplemented by energy transfer from additional LHCII trimers in state II, whose binding is sensitive to digitonin, and which are absent in DeltaLhca4. The grana margins of the thylakoid membrane were found to be the primary site of interaction between this 'extra' LHCII and the PSI-LHCI-LHCII supercomplex in state II. The results suggest that the LHCI complexes mediate energetic interactions between LHCII and PSI in the intact membrane.},
	language = {en},
	number = {12},
	urldate = {2021-06-07},
	journal = {Nat Plants},
	author = {Benson, S. L. and Maheswaran, P. and Ware, M. A. and Hunter, C. N. and Horton, P. and Jansson, S. and Ruban, A. V. and Johnson, M. P.},
	month = nov,
	year = {2015},
	note = {Edition: 2015/01/01},
	pages = {15176},
}

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