1y6i

<table><tr><td colspan='2'>[[1y6i]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Aphanocapsa_sp._(strain_n-1) Aphanocapsa sp. (strain n-1)]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Y6I OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1Y6I FirstGlance]. <br>

</td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">gun4 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1148 Aphanocapsa sp. (strain N-1)])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1y6i FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1y6i OCA], [http://pdbe.org/1y6i PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1y6i RCSB], [http://www.ebi.ac.uk/pdbsum/1y6i PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1y6i ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

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.

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<ref>PMID:15884974</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Chory, J]]

[[Category: Ferrer, J L]]

[[Category: Larkin, R M]]

[[Category: Noel, J P]]

[[Category: Riek, R]]

[[Category: Verdecia, M A]]

[[Category: Porphyrin binding]]