1phw
From Proteopedia
(New page: 200px<br /><applet load="1phw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1phw, resolution 2.36Å" /> '''Crystal structure of...) |
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| - | [[Image:1phw.gif|left|200px]]<br /><applet load="1phw" size=" | + | [[Image:1phw.gif|left|200px]]<br /><applet load="1phw" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1phw, resolution 2.36Å" /> | caption="1phw, resolution 2.36Å" /> | ||
'''Crystal structure of KDO8P synthase in its binary complex with substrate analog 1-deoxy-A5P'''<br /> | '''Crystal structure of KDO8P synthase in its binary complex with substrate analog 1-deoxy-A5P'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The enzyme 3-deoxy-D-manno-2-octulosonate-8-phosphate synthase (KDO8PS) | + | The enzyme 3-deoxy-D-manno-2-octulosonate-8-phosphate synthase (KDO8PS) catalyses the condensation of arabinose 5-phosphate (A5P) and phosphoenol pyruvate (PEP) to obtain 3-deoxy-D-manno-2-octulosonate-8-phosphate (KDO8P). We have elucidated initial modes of ligand binding in KDO8PS binary complexes by X-ray crystallography. Structures of the apo-enzyme and of binary complexes with the substrate PEP, the product KDO8P and the catalytically inactive 1-deoxy analog of arabinose 5-phosphate (1dA5P) were obtained. The KDO8PS active site resembles an irregular funnel with positive electrostatic potential situated at the bottom of the PEP-binding sub-site, which is the primary attractive force towards negatively charged phosphate moieties of all ligands. The structures of the ligand-free apo-KDO8PS and the binary complex with the product KDO8P visualize for the first time the role of His202 as an active-site gate. Examination of the crystal structures of KDO8PS with the KDO8P or 1dA5P shows these ligands bound to the enzyme in the PEP-binding sub-site, and not as expected to the A5P sub-site. Taken together, the structures presented here strengthen earlier evidence that this enzyme functions predominantly through positional catalysis, map out the roles of active-site residues and provide evidence that explains the total lack of catalytic reversibility. |
==About this Structure== | ==About this Structure== | ||
| - | 1PHW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with ROB as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/3-deoxy-8-phosphooctulonate_synthase 3-deoxy-8-phosphooctulonate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.55 2.5.1.55] Full crystallographic information is available from [http:// | + | 1PHW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=ROB:'>ROB</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/3-deoxy-8-phosphooctulonate_synthase 3-deoxy-8-phosphooctulonate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.5.1.55 2.5.1.55] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PHW OCA]. |
==Reference== | ==Reference== | ||
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[[Category: lyase]] | [[Category: lyase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:28:56 2008'' |
Revision as of 12:28, 21 February 2008
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Crystal structure of KDO8P synthase in its binary complex with substrate analog 1-deoxy-A5P
Overview
The enzyme 3-deoxy-D-manno-2-octulosonate-8-phosphate synthase (KDO8PS) catalyses the condensation of arabinose 5-phosphate (A5P) and phosphoenol pyruvate (PEP) to obtain 3-deoxy-D-manno-2-octulosonate-8-phosphate (KDO8P). We have elucidated initial modes of ligand binding in KDO8PS binary complexes by X-ray crystallography. Structures of the apo-enzyme and of binary complexes with the substrate PEP, the product KDO8P and the catalytically inactive 1-deoxy analog of arabinose 5-phosphate (1dA5P) were obtained. The KDO8PS active site resembles an irregular funnel with positive electrostatic potential situated at the bottom of the PEP-binding sub-site, which is the primary attractive force towards negatively charged phosphate moieties of all ligands. The structures of the ligand-free apo-KDO8PS and the binary complex with the product KDO8P visualize for the first time the role of His202 as an active-site gate. Examination of the crystal structures of KDO8PS with the KDO8P or 1dA5P shows these ligands bound to the enzyme in the PEP-binding sub-site, and not as expected to the A5P sub-site. Taken together, the structures presented here strengthen earlier evidence that this enzyme functions predominantly through positional catalysis, map out the roles of active-site residues and provide evidence that explains the total lack of catalytic reversibility.
About this Structure
1PHW is a Single protein structure of sequence from Escherichia coli with as ligand. Active as 3-deoxy-8-phosphooctulonate synthase, with EC number 2.5.1.55 Full crystallographic information is available from OCA.
Reference
Crystal structures of Escherichia coli KDO8P synthase complexes reveal the source of catalytic irreversibility., Vainer R, Belakhov V, Rabkin E, Baasov T, Adir N, J Mol Biol. 2005 Aug 19;351(3):641-52. PMID:16023668
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