This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1y6i
From Proteopedia
(New page: 200px<br /><applet load="1y6i" size="450" color="white" frame="true" align="right" spinBox="true" caption="1y6i, resolution 1.78Å" /> '''Synechocystis GUN4''...) |
|||
| Line 1: | Line 1: | ||
| - | [[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== | ||
| Line 14: | Line 14: | ||
[[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
|
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
Page seeded by OCA on Thu Feb 21 16:02:13 2008
