1xg0
From Proteopedia
(New page: 200px<br /><applet load="1xg0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xg0, resolution 0.97Å" /> '''High resolution crys...) |
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| - | [[Image:1xg0.gif|left|200px]]<br /><applet load="1xg0" size=" | + | [[Image:1xg0.gif|left|200px]]<br /><applet load="1xg0" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xg0, resolution 0.97Å" /> | caption="1xg0, resolution 0.97Å" /> | ||
'''High resolution crystal structure of phycoerythrin 545 from the marine cryptophyte rhodomonas CS24'''<br /> | '''High resolution crystal structure of phycoerythrin 545 from the marine cryptophyte rhodomonas CS24'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Cryptophyte algae differ from cyanobacteria and red algae in the | + | Cryptophyte algae differ from cyanobacteria and red algae in the architecture of their photosynthetic light harvesting systems, even though all three are evolutionarily related. Central to cryptophyte light harvesting is the soluble antenna protein phycoerythrin 545 (PE545). The ultrahigh resolution crystal structure of PE545, isolated from a unicellular cryptophyte Rhodomonas CS24, is reported at both 1.1A and 0.97A resolution, revealing details of the conformation and environments of the chromophores. Absorption, emission and polarized steady state spectroscopy (298K, 77K), as well as ultrafast (20fs time resolution) measurements of population dynamics are reported. Coupled with complementary quantum chemical calculations of electronic transitions of the bilins, these enable assignment of spectral absorption characteristics to each chromophore in the structure. Spectral differences between the tetrapyrrole pigments due to chemical differences between bilins, as well as their binding and interaction with the local protein environment are described. Based on these assignments, and considering customized optical properties such as strong coupling, a model for light harvesting by PE545 is developed which explains the fast, directional harvesting of excitation energy. The excitation energy is funnelled from four peripheral pigments (beta158,beta82) into a central chromophore dimer (beta50/beta61) in approximately 1ps. Those chromophores, in turn, transfer the excitation energy to the red absorbing molecules located at the periphery of the complex in approximately 4ps. A final resonance energy transfer step sensitizes just one of the alpha19 bilins on a time scale of 22ps. Furthermore, it is concluded that binding of PE545 to the thylakoid membrane is not essential for efficient energy transfer to the integral membrane chlorophyll a-containing complexes associated with PS-II. |
==About this Structure== | ==About this Structure== | ||
| - | 1XG0 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Rhodomonas_sp. Rhodomonas sp.] with CL, MG, DBV and PEB as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1XG0 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Rhodomonas_sp. Rhodomonas sp.] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=DBV:'>DBV</scene> and <scene name='pdbligand=PEB:'>PEB</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XG0 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Rhodomonas sp.]] | [[Category: Rhodomonas sp.]] | ||
| - | [[Category: Curmi, P | + | [[Category: Curmi, P M.G.]] |
| - | [[Category: Doust, A | + | [[Category: Doust, A B.]] |
| - | [[Category: Harrop, S | + | [[Category: Harrop, S J.]] |
| - | [[Category: Marai, C | + | [[Category: Marai, C N.J.]] |
| - | [[Category: Scholes, G | + | [[Category: Scholes, G D.]] |
| - | [[Category: Wilk, K | + | [[Category: Wilk, K E.]] |
[[Category: CL]] | [[Category: CL]] | ||
[[Category: DBV]] | [[Category: DBV]] | ||
| Line 27: | Line 27: | ||
[[Category: phycoerythrin]] | [[Category: phycoerythrin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:54:28 2008'' |
Revision as of 13:54, 21 February 2008
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High resolution crystal structure of phycoerythrin 545 from the marine cryptophyte rhodomonas CS24
Overview
Cryptophyte algae differ from cyanobacteria and red algae in the architecture of their photosynthetic light harvesting systems, even though all three are evolutionarily related. Central to cryptophyte light harvesting is the soluble antenna protein phycoerythrin 545 (PE545). The ultrahigh resolution crystal structure of PE545, isolated from a unicellular cryptophyte Rhodomonas CS24, is reported at both 1.1A and 0.97A resolution, revealing details of the conformation and environments of the chromophores. Absorption, emission and polarized steady state spectroscopy (298K, 77K), as well as ultrafast (20fs time resolution) measurements of population dynamics are reported. Coupled with complementary quantum chemical calculations of electronic transitions of the bilins, these enable assignment of spectral absorption characteristics to each chromophore in the structure. Spectral differences between the tetrapyrrole pigments due to chemical differences between bilins, as well as their binding and interaction with the local protein environment are described. Based on these assignments, and considering customized optical properties such as strong coupling, a model for light harvesting by PE545 is developed which explains the fast, directional harvesting of excitation energy. The excitation energy is funnelled from four peripheral pigments (beta158,beta82) into a central chromophore dimer (beta50/beta61) in approximately 1ps. Those chromophores, in turn, transfer the excitation energy to the red absorbing molecules located at the periphery of the complex in approximately 4ps. A final resonance energy transfer step sensitizes just one of the alpha19 bilins on a time scale of 22ps. Furthermore, it is concluded that binding of PE545 to the thylakoid membrane is not essential for efficient energy transfer to the integral membrane chlorophyll a-containing complexes associated with PS-II.
About this Structure
1XG0 is a Protein complex structure of sequences from Rhodomonas sp. with , , and as ligands. Full crystallographic information is available from OCA.
Reference
Developing a structure-function model for the cryptophyte phycoerythrin 545 using ultrahigh resolution crystallography and ultrafast laser spectroscopy., Doust AB, Marai CN, Harrop SJ, Wilk KE, Curmi PM, Scholes GD, J Mol Biol. 2004 Nov 12;344(1):135-53. PMID:15504407
Page seeded by OCA on Thu Feb 21 15:54:28 2008
Categories: Protein complex | Rhodomonas sp. | Curmi, P M.G. | Doust, A B. | Harrop, S J. | Marai, C N.J. | Scholes, G D. | Wilk, K E. | CL | DBV | MG | PEB | Cryptophyte | Light-harvesting protein | Phycoerythrin
