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- | [[Image:1jcy.gif|left|200px]] | + | {{Seed}} |
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| {{STRUCTURE_1jcy| PDB=1jcy | SCENE= }} | | {{STRUCTURE_1jcy| PDB=1jcy | SCENE= }} |
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- | '''Aquifex aeolicus KDO8P synthase in complex with R5P, PEP and Cadmium'''
| + | ===Aquifex aeolicus KDO8P synthase in complex with R5P, PEP and Cadmium=== |
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- | ==Overview==
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- | We have determined the crystal structures of the metalloenzyme 3-deoxy-D-manno-octulosonate 8-phosphate (KDO8P) synthase from Aquifex aeolicus in complex with phosphoenolpyruvate (PEP) and ribose 5-phosphate (R5P), and with a bisubstrate inhibitor that mimics the postulated linear reaction intermediate. R5P, which is not a substrate for KDO8P synthase, binds in a manner similar to that of arabinose 5-phosphate (A5P), which is the natural substrate. The lack of reactivity of R5P appears to be primarily a consequence of the loss of a water molecule coordinated to Cd(2+) and located on the si side of PEP. This water molecule is no longer present because it cannot form a hydrogen bond with C2-OH(R5P), which is oriented in a different direction from C2-OH(A5P). The bisubstrate inhibitor binds with its phosphate and phosphonate moieties occupying the positions of the phosphate groups of A5P and PEP, respectively. One of the inhibitor hydroxyls replaces water as a ligand of Cd(2+). The current work supports a mechanism for the synthesis of KDO8P, in which a hydroxide ion on the si side of PEP attacks C2(PEP), forming a tetrahedral-like intermediate with a buildup of negative charge at C3(PEP). The ensuing condensation of C3(PEP) with C1(A5P) would be favored by a proton transfer from the phosphate moiety of PEP to the aldehyde carbonyl of A5P to generate the hydroxyl. Overall, the process can be described as a syn addition of water and A5P to the si side of PEP.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_11747443}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 11747443 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_11747443}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Pep]] | | [[Category: Pep]] |
| [[Category: R5p]] | | [[Category: R5p]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:04:19 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 20:02:43 2008'' |
Revision as of 17:02, 1 July 2008
Template:STRUCTURE 1jcy
Aquifex aeolicus KDO8P synthase in complex with R5P, PEP and Cadmium
Template:ABSTRACT PUBMED 11747443
About this Structure
1JCY is a Single protein structure of sequence from Aquifex aeolicus. Full crystallographic information is available from OCA.
Reference
Structures of Aquifex aeolicus KDO8P synthase in complex with R5P and PEP, and with a bisubstrate inhibitor: role of active site water in catalysis., Wang J, Duewel HS, Woodard RW, Gatti DL, Biochemistry. 2001 Dec 25;40(51):15676-83. PMID:11747443
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