7prc
From Proteopedia
(New page: 200px<br /><applet load="7prc" size="450" color="white" frame="true" align="right" spinBox="true" caption="7prc, resolution 2.65Å" /> '''PHOTOSYNTHETIC REACT...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:7prc.gif|left|200px]]<br /><applet load="7prc" size=" | + | [[Image:7prc.gif|left|200px]]<br /><applet load="7prc" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="7prc, resolution 2.65Å" /> | caption="7prc, resolution 2.65Å" /> | ||
'''PHOTOSYNTHETIC REACTION CENTER FROM RHODOPSEUDOMONAS VIRIDIS (DG-420315 (TRIAZINE) COMPLEX)'''<br /> | '''PHOTOSYNTHETIC REACTION CENTER FROM RHODOPSEUDOMONAS VIRIDIS (DG-420315 (TRIAZINE) COMPLEX)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | In a reaction of central importance to the energetics of photosynthetic | + | In a reaction of central importance to the energetics of photosynthetic bacteria, light-induced electron transfer in the reaction centre (RC) is coupled with the uptake of protons from the cytoplasm at the binding site of the secondary quinone (QB). It has been established by X-ray crystallography that the triazine herbicide terbutryn binds to the QB site. However, the exact description of protein-triazine interactions has had to await the refinement of higher-resolution structures. In addition, there is also interest in the role of chirality in the activity of herbicides. Here, we report the structural characterisation of triazine binding by crystallographic refinement of complexes of the RC either with the triazine inhibitor atrazine (Protein Data Bank (PDB) entry 5PRC) or with the chiral atrazine derivatives, DG-420314 (S(-) enantiomer, PDB entry 6PRC) or DG-420315 (R(+) enantiomer, PDB entry 7PRC). Due to the high quality of the data collected, it has been possible to describe the exact nature of triazine binding and its effect on the structure of the protein at high-resolution limits of 2.35 A (5PRC), 2.30 A (6PRC), and 2.65 A (7PRC), respectively. In addition to two previously implied hydrogen bonds, a third hydrogen bond, binding the distal side of the inhibitors to the protein, and four additional hydrogen bonds mediated by two tightly bound water molecules on the proximal side of the inhibitors, are apparent. Based on the high quality data collected on the RC complexes of the two chiral atrazine derivatives, unequivocal assignment of the structure at the chiral centres was possible, even though the differences in structures of the substituents are small. The structures provide explanations for the relative binding affinities of the two chiral compounds. Although it was not an explicit goal of this work, the new data were of sufficient quality to improve the original model also regarding the structure of the bound carotenoid 1,2-dihydroneurosporene. A carotenoid model with a cis double bond at the 15,15' position fits the electron density better than the original model with a 13,14-cis double bond. |
==About this Structure== | ==About this Structure== | ||
| - | 7PRC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Blastochloris_viridis Blastochloris viridis] with FE2, SO4, BCB, BPB, MQ7, HEM, NS5, CET and LDA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 7PRC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Blastochloris_viridis Blastochloris viridis] with <scene name='pdbligand=FE2:'>FE2</scene>, <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=BCB:'>BCB</scene>, <scene name='pdbligand=BPB:'>BPB</scene>, <scene name='pdbligand=MQ7:'>MQ7</scene>, <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=NS5:'>NS5</scene>, <scene name='pdbligand=CET:'>CET</scene> and <scene name='pdbligand=LDA:'>LDA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7PRC OCA]. |
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Blastochloris viridis]] | [[Category: Blastochloris viridis]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Lancaster, C | + | [[Category: Lancaster, C R.D.]] |
[[Category: Michel, H.]] | [[Category: Michel, H.]] | ||
[[Category: BCB]] | [[Category: BCB]] | ||
| Line 28: | Line 28: | ||
[[Category: triazine inhibitor]] | [[Category: triazine inhibitor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:17:27 2008'' |
Revision as of 17:17, 21 February 2008
|
PHOTOSYNTHETIC REACTION CENTER FROM RHODOPSEUDOMONAS VIRIDIS (DG-420315 (TRIAZINE) COMPLEX)
Overview
In a reaction of central importance to the energetics of photosynthetic bacteria, light-induced electron transfer in the reaction centre (RC) is coupled with the uptake of protons from the cytoplasm at the binding site of the secondary quinone (QB). It has been established by X-ray crystallography that the triazine herbicide terbutryn binds to the QB site. However, the exact description of protein-triazine interactions has had to await the refinement of higher-resolution structures. In addition, there is also interest in the role of chirality in the activity of herbicides. Here, we report the structural characterisation of triazine binding by crystallographic refinement of complexes of the RC either with the triazine inhibitor atrazine (Protein Data Bank (PDB) entry 5PRC) or with the chiral atrazine derivatives, DG-420314 (S(-) enantiomer, PDB entry 6PRC) or DG-420315 (R(+) enantiomer, PDB entry 7PRC). Due to the high quality of the data collected, it has been possible to describe the exact nature of triazine binding and its effect on the structure of the protein at high-resolution limits of 2.35 A (5PRC), 2.30 A (6PRC), and 2.65 A (7PRC), respectively. In addition to two previously implied hydrogen bonds, a third hydrogen bond, binding the distal side of the inhibitors to the protein, and four additional hydrogen bonds mediated by two tightly bound water molecules on the proximal side of the inhibitors, are apparent. Based on the high quality data collected on the RC complexes of the two chiral atrazine derivatives, unequivocal assignment of the structure at the chiral centres was possible, even though the differences in structures of the substituents are small. The structures provide explanations for the relative binding affinities of the two chiral compounds. Although it was not an explicit goal of this work, the new data were of sufficient quality to improve the original model also regarding the structure of the bound carotenoid 1,2-dihydroneurosporene. A carotenoid model with a cis double bond at the 15,15' position fits the electron density better than the original model with a 13,14-cis double bond.
About this Structure
7PRC is a Protein complex structure of sequences from Blastochloris viridis with , , , , , , , and as ligands. Full crystallographic information is available from OCA.
Reference
Refined crystal structures of reaction centres from Rhodopseudomonas viridis in complexes with the herbicide atrazine and two chiral atrazine derivatives also lead to a new model of the bound carotenoid., Lancaster CR, Michel H, J Mol Biol. 1999 Feb 26;286(3):883-98. PMID:10024457
Page seeded by OCA on Thu Feb 21 19:17:27 2008
Categories: Blastochloris viridis | Protein complex | Lancaster, C R.D. | Michel, H. | BCB | BPB | CET | FE2 | HEM | LDA | MQ7 | NS5 | SO4 | Photosynthetic reaction center | Secondary quinone (qb) | Triazine inhibitor
