2v6a: Difference between revisions

Revision as of 18:15, 4 May 2008

CRYSTAL STRUCTURE OF CHLAMYDOMONAS REINHARDTII RUBISCO WITH LARGE-SUBUNIT MUTATIONS V331A, G344S

OverviewOverview

The loop between alpha-helix 6 and beta-strand 6 in the alpha/beta-barrel of ribulose-1,5-bisphosphate carboxylase/oxygenase plays a key role in discriminating between CO2 and O2. Genetic screening in Chlamydomonas reinhardtii previously identified a loop-6 V331A substitution that decreases carboxylation and CO2/O2 specificity. Revertant selection identified T342I and G344S substitutions that restore photosynthetic growth by increasing carboxylation and specificity of the V331A enzyme. In numerous X-ray crystal structures, loop 6 is closed or open depending on the activation state of the enzyme and the presence or absence of ligands. The carboxy terminus folds over loop 6 in the closed state. To study the molecular basis for catalysis, directed mutagenesis and chloroplast transformation were used to create T342I and G344S substitutions alone. X-ray crystal structures were then solved for the V331A, V331A/T342I, T342I, and V331A/G344S enzymes, as well as for a D473E enzyme created to assess the role of the carboxy terminus in loop-6 closure. V331A disturbs a hydrophobic pocket, abolishing several van der Waals interactions. These changes are complemented by T342I and G344S, both of which alone cause decreases in CO2/O2 specificity. In the V331A/T342I revertant enzyme, Arg339 main-chain atoms are displaced. In V331A/G344S, alpha-helix 6 is shifted. D473E causes disorder of the carboxy terminus, but loop 6 remains closed. Interactions between a transition-state analogue and several residues are altered in the mutant enzymes. However, active-site Lys334 at the apex of loop 6 has a normal conformation. A variety of subtle interactions must be responsible for catalytic efficiency and CO2/O2 specificity.

About this StructureAbout this Structure

2V6A is a Protein complex structure of sequences from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA.

ReferenceReference

Structural analysis of altered large-subunit loop-6/carboxy-terminus interactions that influence catalytic efficiency and CO2/O2 specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase., Karkehabadi S, Satagopan S, Taylor TC, Spreitzer RJ, Andersson I, Biochemistry. 2007 Oct 2;46(39):11080-9. Epub 2007 Sep 8. PMID:17824672 Page seeded by OCA on Sun May 4 18:15:56 2008

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OCA

@@ Line 1: / Line 1: @@
 [[Image:2v6a.jpg|left|200px]]
- {{Structure
+<!--
-|PDB= 2v6a |SIZE=350|CAPTION= <scene name='initialview01'>2v6a</scene>, resolution 1.50&Aring;
+The line below this paragraph, containing "STRUCTURE_2v6a", creates the "Structure Box" on the page.
-|SITE= <scene name='pdbsite=AC1:Edo+Binding+Site+For+Chain+L'>AC1</scene>
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=CAP:2-CARBOXYARABINITOL-1,5-DIPHOSPHATE'>CAP</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=HYP:4-HYDROXYPROLINE'>HYP</scene>, <scene name='pdbligand=KCX:LYSINE+NZ-CARBOXYLIC+ACID'>KCX</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=MME:N-METHYL+METHIONINE'>MME</scene>, <scene name='pdbligand=SMC:S-METHYLCYSTEINE'>SMC</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Ribulose-bisphosphate_carboxylase Ribulose-bisphosphate carboxylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.1.1.39 4.1.1.39] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_2v6a|  PDB=2v6a  |  SCENE=  }}
-|RELATEDENTRY=[[1gk8|1GK8]], [[1uwa|1UWA]], [[1uw9|1UW9]], [[1uzh|1UZH]], [[1ir2|1IR2]], [[1uzd|1UZD]], [[2v63|2V63]], [[2v67|2V67]], [[2v68|2V68]], [[2v69|2V69]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2v6a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2v6a OCA], [http://www.ebi.ac.uk/pdbsum/2v6a PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2v6a RCSB]</span>
-}}
 '''CRYSTAL STRUCTURE OF CHLAMYDOMONAS REINHARDTII RUBISCO WITH LARGE-SUBUNIT MUTATIONS V331A, G344S'''
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 [[Category: Spreitzer, R J.]]
 [[Category: Taylor, T C.]]
-[[Category: acetylation]]
+[[Category: Acetylation]]
-[[Category: calvin cycle]]
+[[Category: Calvin cycle]]
-[[Category: carbon dioxide fixation]]
+[[Category: Carbon dioxide fixation]]
-[[Category: chloroplast]]
+[[Category: Chloroplast]]
-[[Category: co2/o2 specificity]]
+[[Category: Co2/o2 specificity]]
-[[Category: hydroxylation]]
+[[Category: Hydroxylation]]
-[[Category: large subunit loop 6 mutation]]
+[[Category: Large subunit loop 6 mutation]]
-[[Category: lyase]]
+[[Category: Lyase]]
-[[Category: magnesium]]
+[[Category: Magnesium]]
-[[Category: metal-binding]]
+[[Category: Metal-binding]]
-[[Category: methylation]]
+[[Category: Methylation]]
-[[Category: monooxygenase]]
+[[Category: Monooxygenase]]
-[[Category: oxidoreductase]]
+[[Category: Oxidoreductase]]
-[[Category: photorespiration]]
+[[Category: Photorespiration]]
-[[Category: photosynthesis]]
+[[Category: Photosynthesis]]
-[[Category: plastid]]
+[[Category: Plastid]]
-[[Category: rubisco]]
+[[Category: Rubisco]]
-[[Category: transit peptide]]
+[[Category: Transit peptide]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 18:15:56 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 05:08:47 2008''