MPI für bioanorganische Chemie / MPI für bioanorganische Chemie |
|The terminal phycobilisome emitter, LCM: A light-harvesting pigment with a phytochrome chromophore|
|Authors:||Tang, Kun; Ding, Wen-Long; Höppner, Astrid; Zhao, Cheng; Zhang, Lun; Hontani, Yusaku; Kennis, John T. M.; Gärtner, Wolfgang; Scheer, Hugo; Zhou, Ming; Zhao, Kai-Hong|
|Date of Publication (YYYY-MM-DD):||2015|
|Title of Journal:||Proceedings of the National Academy of Sciences of the United States of America|
|Issue / Number:||52|
|Review Status:||Internal review|
|Abstract / Description:||Photosynthesis relies on energy transfer from light-harvesting complexes to reaction centers. Phycobilisomes, the light-harvesting antennas in cyanobacteria and red algae, attach to the membrane via the multidomain core-membrane linker, L-CM. The chromophore domain of L-CM forms a bottleneck for funneling the harvested energy either productively to reaction centers or, in case of light overload, to quenchers like orange carotenoid protein (OCP) that prevent photodamage. The crystal structure of the solubly modified chromophore domain from Nostoc sp. PCC7120 was resolved at 2.2 angstrom. Although its protein fold is similar to the protein folds of phycobiliproteins, the phycocyanobilin (PCB) chromophore adopts ZZZssa geometry, which is unknown among phycobiliproteins but characteristic for sensory photoreceptors (phytochromes and cyanobacteriochromes). However, chromophore photoisomerization is inhibited in L-CM by tight packing. The ZZZssa geometry of the chromophore and p-p stacking with a neighboring Trp account for the functionally relevant extreme spectral red shift of L-CM. Exciton coupling is excluded by the large distance between two PCBs in a homodimer and by preservation of the spectral features in monomers. The structure also indicates a distinct flexibility that could be involved in quenching. The conclusions from the crystal structure are supported by femtosecond transient absorption spectra in solution.|
|Comment of the Author/Creator:||Date: 2015, DEC 29 2015|
|External Publication Status:||published|
|Version Comment:||Automatic journal name synchronization|
|Communicated by:||N. N.|
|Affiliations:||MPI für bioanorganische Chemie|
|External Affiliations:||[Tang,K.; Ding,W.L.; Zhao,C.; Zhang,L.; Zhou,M.] Huazhong Agr Univ, State Key Lab Agr Microbiol, Wuhan 430070, Peoples R China
[Höppner,A.;] Univ.Düsseldorf, Xray Facil.& Crystal.Farm., D-40225 Düsseldorf, Germany.
[Hontani,Y.; Kennis,J.T.M.] Vrije Univ.Amsterdam, Fac.Sci., Dept.Phys.& Astron., Biophys.Sect., NL-1081 HV Amsterdam, Netherlands.
[Scheer,H.] Univ.Munich, Dept.Biol.1, D-80638 Munich, Germany.
|Identifiers:||ISI:000367234700049 [ID No:1] |
ISSN:0027-8424 [ID No:2]
DOI:10.1073/pnas.1519177113 [ID No:3]
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