2v63: Difference between revisions
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==Overview== | ==Overview== | ||
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, ... | 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 Structure== | ==About this Structure== | ||
2V63 is a | 2V63 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii Chlamydomonas reinhardtii] with MG, CAP and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2V63 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transit peptide]] | [[Category: transit peptide]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:33:17 2007'' | ||
Revision as of 13:27, 5 November 2007
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CRYSTAL STRUCTURE OF RUBISCO FROM CHLAMYDOMONAS REINHARDTII WITH A LARGE-SUBUNIT V331A MUTATION
Overview
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 Structure
2V63 is a Protein complex structure of sequences from Chlamydomonas reinhardtii with MG, CAP and EDO as ligands. Active as Ribulose-bisphosphate carboxylase, with EC number 4.1.1.39 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
Structural Analysis of Altered Large-Subunit Loop-6/Carboxy-Terminus Interactions That Influence Catalytic Efficiency and CO(2)/O(2) 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
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Proteopedia Page Contributors and Editors (what is this?)
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- Chlamydomonas reinhardtii
- Protein complex
- Ribulose-bisphosphate carboxylase
- Andersson, I.
- Karkehabadi, S.
- Satagopan, S.
- Spreitzer, R.J.
- Taylor, T.C.
- CAP
- EDO
- MG
- Acetylation
- Calvin cycle
- Carbon dioxide fixation
- Chloroplast
- Co2/o2 specificity
- Hydroxylation
- Large subunit loop 6 mutation
- Lyase
- Magnesium
- Metal-binding
- Methylation
- Monooxygenase
- Oxidoreductase
- Photorespiration
- Photosynthesis
- Plastid
- Rubisco
- Transit peptide
