1y6i: Difference between revisions
New page: left|200px<br /><applet load="1y6i" size="450" color="white" frame="true" align="right" spinBox="true" caption="1y6i, resolution 1.78Å" /> '''Synechocystis GUN4''... |
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[[Image:1y6i.gif|left|200px]]<br /><applet load="1y6i" size=" | [[Image:1y6i.gif|left|200px]]<br /><applet load="1y6i" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1y6i, resolution 1.78Å" /> | caption="1y6i, resolution 1.78Å" /> | ||
'''Synechocystis GUN4'''<br /> | '''Synechocystis GUN4'''<br /> | ||
==Overview== | ==Overview== | ||
In plants, the accumulation of the chlorophyll precursor Mg-protoporphyrin | In plants, the accumulation of the chlorophyll precursor Mg-protoporphyrin IX (Mg-Proto) in the plastid regulates the expression of a number of nuclear genes with functions related to photosynthesis. Analysis of the plastid-to-nucleus signaling activity of Mg-Proto in Arabidopsis thaliana led to the discovery of GUN4, a novel porphyrin-binding protein that also dramatically enhances the activity of Mg-chelatase, the enzyme that synthesizes Mg-Proto. GUN4 may also play a role in both photoprotection and the cellular shuttling of tetrapyrroles. Here we report a 1.78-A resolution crystal structure of Synechocystis GUN4, in which the porphyrin-binding domain adopts a unique three dimensional fold with a "cupped hand" shape. Biophysical and biochemical analyses revealed the specific site of interaction between GUN4 and Mg-Proto and the energetic determinants for the GUN4.Mg-Proto interaction. Our data support a novel protective function for GUN4 in tetrapyrrole trafficking. The combined structural and energetic analyses presented herein form the physical-chemical basis for understanding GUN4 biological activity, including its role in the stimulation of Mg-chelatase activity, as well as in Mg-Proto retrograde signaling. | ||
==About this Structure== | ==About this Structure== | ||
1Y6I is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Synechocystis_sp. Synechocystis sp.]. Full crystallographic information is available from [http:// | 1Y6I is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Synechocystis_sp. Synechocystis sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Y6I OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Synechocystis sp.]] | [[Category: Synechocystis sp.]] | ||
[[Category: Chory, J.]] | [[Category: Chory, J.]] | ||
[[Category: Ferrer, J | [[Category: Ferrer, J L.]] | ||
[[Category: Larkin, R | [[Category: Larkin, R M.]] | ||
[[Category: Noel, J | [[Category: Noel, J P.]] | ||
[[Category: Riek, R.]] | [[Category: Riek, R.]] | ||
[[Category: Verdecia, M | [[Category: Verdecia, M A.]] | ||
[[Category: helix-bundle]] | [[Category: helix-bundle]] | ||
[[Category: porphyrin binding]] | [[Category: porphyrin binding]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:02:13 2008'' | ||
Revision as of 14:02, 21 February 2008
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Synechocystis GUN4
Overview
In plants, the accumulation of the chlorophyll precursor Mg-protoporphyrin IX (Mg-Proto) in the plastid regulates the expression of a number of nuclear genes with functions related to photosynthesis. Analysis of the plastid-to-nucleus signaling activity of Mg-Proto in Arabidopsis thaliana led to the discovery of GUN4, a novel porphyrin-binding protein that also dramatically enhances the activity of Mg-chelatase, the enzyme that synthesizes Mg-Proto. GUN4 may also play a role in both photoprotection and the cellular shuttling of tetrapyrroles. Here we report a 1.78-A resolution crystal structure of Synechocystis GUN4, in which the porphyrin-binding domain adopts a unique three dimensional fold with a "cupped hand" shape. Biophysical and biochemical analyses revealed the specific site of interaction between GUN4 and Mg-Proto and the energetic determinants for the GUN4.Mg-Proto interaction. Our data support a novel protective function for GUN4 in tetrapyrrole trafficking. The combined structural and energetic analyses presented herein form the physical-chemical basis for understanding GUN4 biological activity, including its role in the stimulation of Mg-chelatase activity, as well as in Mg-Proto retrograde signaling.
About this Structure
1Y6I is a Single protein structure of sequence from Synechocystis sp.. Full crystallographic information is available from OCA.
Reference
Structure of the Mg-chelatase cofactor GUN4 reveals a novel hand-shaped fold for porphyrin binding., Verdecia MA, Larkin RM, Ferrer JL, Riek R, Chory J, Noel JP, PLoS Biol. 2005 May;3(5):e151. Epub 2005 Apr 26. PMID:15884974
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