View source for 1qgn


==CYSTATHIONINE GAMMA-SYNTHASE FROM NICOTIANA TABACUM==
<StructureSection load='1qgn' size='340' side='right'caption='[[1qgn]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1qgn]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Nicotiana_tabacum Nicotiana tabacum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QGN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QGN FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.9&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PLP:PYRIDOXAL-5-PHOSPHATE'>PLP</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1qgn FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qgn OCA], [https://pdbe.org/1qgn PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qgn RCSB], [https://www.ebi.ac.uk/pdbsum/1qgn PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qgn ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q9ZPL5_TOBAC Q9ZPL5_TOBAC] 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/qg/1qgn_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1qgn ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
Cystathionine gamma-synthase catalyses the committed step of de novo methionine biosynthesis in micro-organisms and plants, making the enzyme an attractive target for the design of new antibiotics and herbicides. The crystal structure of cystathionine gamma-synthase from Nicotiana tabacum has been solved by Patterson search techniques using the structure of Escherichia coli cystathionine gamma-synthase. The model was refined at 2.9 A resolution to a crystallographic R -factor of 20.1 % (Rfree25.0 %). The physiological substrates of the enzyme, L-homoserine phosphate and L-cysteine, were modelled into the unliganded structure. These complexes support the proposed ping-pong mechanism for catalysis and illustrate the dissimilar substrate specificities of bacterial and plant cystathionine gamma-synthases on a molecular level. The main difference arises from the binding modes of the distal substrate groups (O -acetyl/succinyl versusO -phosphate). Central in fixing the distal phosphate of the plant CGS substrate is an exposed lysine residue that is strictly conserved in plant cystathionine gamma-synthases whereas bacterial enzymes carry a glycine residue at this position. General insight regarding the reaction specificity of transsulphuration enzymes is gained by the comparison to cystathionine beta-lyase from E. coli, indicating the mechanistic importance of a second substrate binding site for L-cysteine which leads to different chemical reaction types.

The crystal structure of cystathionine gamma-synthase from Nicotiana tabacum reveals its substrate and reaction specificity.,Steegborn C, Messerschmidt A, Laber B, Streber W, Huber R, Clausen T J Mol Biol. 1999 Jul 30;290(5):983-96. PMID:10438597<ref>PMID:10438597</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1qgn" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cystathionine beta-lyase|Cystathionine beta-lyase]]
*[[Cystathionine gamma synthase|Cystathionine gamma synthase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Nicotiana tabacum]]
[[Category: Clausen T]]
[[Category: Huber R]]
[[Category: Laber B]]
[[Category: Messerschmidt A]]
[[Category: Steegborn C]]
[[Category: Streber W]]