7enl
From Proteopedia
(New page: 200px<br /><applet load="7enl" size="450" color="white" frame="true" align="right" spinBox="true" caption="7enl, resolution 2.2Å" /> '''MECHANISM OF ENOLASE:...) |
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| - | [[Image:7enl.gif|left|200px]]<br /><applet load="7enl" size=" | + | [[Image:7enl.gif|left|200px]]<br /><applet load="7enl" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="7enl, resolution 2.2Å" /> | caption="7enl, resolution 2.2Å" /> | ||
'''MECHANISM OF ENOLASE: THE CRYSTAL STRUCTURE OF ENOLASE-MG2+-PHOSPHOGLYCERATE(SLASH) PHOSPHOENOLPYRUVATE COMPLEX AT 2.2-ANGSTROMS RESOLUTION'''<br /> | '''MECHANISM OF ENOLASE: THE CRYSTAL STRUCTURE OF ENOLASE-MG2+-PHOSPHOGLYCERATE(SLASH) PHOSPHOENOLPYRUVATE COMPLEX AT 2.2-ANGSTROMS RESOLUTION'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Enolase in the presence of Mg2+ catalyzes the elimination of H2O from | + | Enolase in the presence of Mg2+ catalyzes the elimination of H2O from 2-phosphoglyceric acid (PGA) to form phosphoenolpyruvate (PEP) and the reverse reaction, the hydration of PEP to PGA. The structure of the ternary complex yeast enolase-Mg2(+)-PGA/PEP has been determined by X-ray diffraction and refined by crystallographic restrained least-squares to an R = 16.9% for those data with I/sigma (I) greater than or equal to 2 to 2.2-A resolution with a good geometry of the model. The structure indicates the substrate molecule in the active site has its hydroxyl group coordinated to the Mg2+ ion. The carboxylic group interacts with the side chains of His373 and Lys396. The phosphate group is H-bonded to the guanidinium group of Arg374. A water molecule H-bonded to the carboxylic groups of Glu168 and Glu211 is located at a 2.6-A distance from carbon-2 of the substrate in the direction of its proton. We propose that this cluster functions as the base abstracting the proton in the catalytic process. The proton is probably transferred, first to the water molecule, then to Glu168, and further to the substrate hydroxyl to form a water molecule. Some analogy is apparent between the initial stages of the enolase reverse reaction, the hydration of PEP, and the proteolytic mechanism of the metallohydrolases carboxypeptidase A and thermolysin. The substrate/product binding is accompanied by large movements of loops Ser36-His43 and Ser158-Gly162. The role of these conformational changes is not clear at this time. |
==About this Structure== | ==About this Structure== | ||
| - | 7ENL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with MG and 2PG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Phosphopyruvate_hydratase Phosphopyruvate hydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.11 4.2.1.11] Full crystallographic information is available from [http:// | + | 7ENL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=2PG:'>2PG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Phosphopyruvate_hydratase Phosphopyruvate hydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.11 4.2.1.11] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7ENL OCA]. |
==Reference== | ==Reference== | ||
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[[Category: carbon-oxygen lyase]] | [[Category: carbon-oxygen lyase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:17:02 2008'' |
Revision as of 17:17, 21 February 2008
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MECHANISM OF ENOLASE: THE CRYSTAL STRUCTURE OF ENOLASE-MG2+-PHOSPHOGLYCERATE(SLASH) PHOSPHOENOLPYRUVATE COMPLEX AT 2.2-ANGSTROMS RESOLUTION
Overview
Enolase in the presence of Mg2+ catalyzes the elimination of H2O from 2-phosphoglyceric acid (PGA) to form phosphoenolpyruvate (PEP) and the reverse reaction, the hydration of PEP to PGA. The structure of the ternary complex yeast enolase-Mg2(+)-PGA/PEP has been determined by X-ray diffraction and refined by crystallographic restrained least-squares to an R = 16.9% for those data with I/sigma (I) greater than or equal to 2 to 2.2-A resolution with a good geometry of the model. The structure indicates the substrate molecule in the active site has its hydroxyl group coordinated to the Mg2+ ion. The carboxylic group interacts with the side chains of His373 and Lys396. The phosphate group is H-bonded to the guanidinium group of Arg374. A water molecule H-bonded to the carboxylic groups of Glu168 and Glu211 is located at a 2.6-A distance from carbon-2 of the substrate in the direction of its proton. We propose that this cluster functions as the base abstracting the proton in the catalytic process. The proton is probably transferred, first to the water molecule, then to Glu168, and further to the substrate hydroxyl to form a water molecule. Some analogy is apparent between the initial stages of the enolase reverse reaction, the hydration of PEP, and the proteolytic mechanism of the metallohydrolases carboxypeptidase A and thermolysin. The substrate/product binding is accompanied by large movements of loops Ser36-His43 and Ser158-Gly162. The role of these conformational changes is not clear at this time.
About this Structure
7ENL is a Single protein structure of sequence from Saccharomyces cerevisiae with and as ligands. Active as Phosphopyruvate hydratase, with EC number 4.2.1.11 Full crystallographic information is available from OCA.
Reference
Mechanism of enolase: the crystal structure of enolase-Mg2(+)-2-phosphoglycerate/phosphoenolpyruvate complex at 2.2-A resolution., Lebioda L, Stec B, Biochemistry. 1991 Mar 19;30(11):2817-22. PMID:2007120
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