1xjj
From Proteopedia
(New page: 200px<br /><applet load="1xjj" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xjj, resolution 1.86Å" /> '''Structural mechanism...) |
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| - | [[Image:1xjj.gif|left|200px]]<br /><applet load="1xjj" size=" | + | [[Image:1xjj.gif|left|200px]]<br /><applet load="1xjj" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1xjj, resolution 1.86Å" /> | caption="1xjj, resolution 1.86Å" /> | ||
'''Structural mechanism of allosteric substrate specificity in a ribonucleotide reductase: dGTP complex'''<br /> | '''Structural mechanism of allosteric substrate specificity in a ribonucleotide reductase: dGTP complex'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides | + | Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides into deoxyribonucleotides, which constitute the precursor pools used for DNA synthesis and repair. Imbalances in these pools increase mutational rates and are detrimental to the cell. Balanced precursor pools are maintained primarily through the regulation of the RNR substrate specificity. Here, the molecular mechanism of the allosteric substrate specificity regulation is revealed through the structures of a dimeric coenzyme B12-dependent RNR from Thermotoga maritima, both in complexes with four effector-substrate nucleotide pairs and in three complexes with only effector. The mechanism is based on the flexibility of loop 2, a key structural element, which forms a bridge between the specificity effector and substrate nucleotides. Substrate specificity is achieved as different effectors and their cognate substrates stabilize specific discrete loop 2 conformations. The mechanism of substrate specificity regulation is probably general for most class I and class II RNRs. |
==About this Structure== | ==About this Structure== | ||
| - | 1XJJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with MG and DGT as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ribonucleoside-diphosphate_reductase Ribonucleoside-diphosphate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.17.4.1 1.17.4.1] Full crystallographic information is available from [http:// | + | 1XJJ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=DGT:'>DGT</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Ribonucleoside-diphosphate_reductase Ribonucleoside-diphosphate reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.17.4.1 1.17.4.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XJJ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Eliasson, R.]] | [[Category: Eliasson, R.]] | ||
[[Category: Jordan, A.]] | [[Category: Jordan, A.]] | ||
| - | [[Category: Larsson, K | + | [[Category: Larsson, K M.]] |
| - | [[Category: Logan, D | + | [[Category: Logan, D T.]] |
[[Category: Nordlund, P.]] | [[Category: Nordlund, P.]] | ||
[[Category: Reichard, P.]] | [[Category: Reichard, P.]] | ||
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[[Category: substrate specificity]] | [[Category: substrate specificity]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:55:25 2008'' |
Revision as of 13:55, 21 February 2008
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Structural mechanism of allosteric substrate specificity in a ribonucleotide reductase: dGTP complex
Overview
Ribonucleotide reductases (RNRs) catalyze the reduction of ribonucleotides into deoxyribonucleotides, which constitute the precursor pools used for DNA synthesis and repair. Imbalances in these pools increase mutational rates and are detrimental to the cell. Balanced precursor pools are maintained primarily through the regulation of the RNR substrate specificity. Here, the molecular mechanism of the allosteric substrate specificity regulation is revealed through the structures of a dimeric coenzyme B12-dependent RNR from Thermotoga maritima, both in complexes with four effector-substrate nucleotide pairs and in three complexes with only effector. The mechanism is based on the flexibility of loop 2, a key structural element, which forms a bridge between the specificity effector and substrate nucleotides. Substrate specificity is achieved as different effectors and their cognate substrates stabilize specific discrete loop 2 conformations. The mechanism of substrate specificity regulation is probably general for most class I and class II RNRs.
About this Structure
1XJJ is a Single protein structure of sequence from Thermotoga maritima with and as ligands. Active as Ribonucleoside-diphosphate reductase, with EC number 1.17.4.1 Full crystallographic information is available from OCA.
Reference
Structural mechanism of allosteric substrate specificity regulation in a ribonucleotide reductase., Larsson KM, Jordan A, Eliasson R, Reichard P, Logan DT, Nordlund P, Nat Struct Mol Biol. 2004 Nov;11(11):1142-9. Epub 2004 Oct 10. PMID:15475969
Page seeded by OCA on Thu Feb 21 15:55:25 2008
Categories: Ribonucleoside-diphosphate reductase | Single protein | Thermotoga maritima | Eliasson, R. | Jordan, A. | Larsson, K M. | Logan, D T. | Nordlund, P. | Reichard, P. | DGT | MG | 10 alpha-beta barrel | Allosteric regulation | Protein-nucleotide complex | Ribonucleotide reductase | Substrate specificity
