1jcx
From Proteopedia
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'''Aquifex aeolicus KDO8P synthase in complex with API and Cadmium''' | '''Aquifex aeolicus KDO8P synthase in complex with API and Cadmium''' | ||
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[[Category: Wang, J.]] | [[Category: Wang, J.]] | ||
[[Category: Woodard, R W.]] | [[Category: Woodard, R W.]] | ||
| - | [[Category: | + | [[Category: Api]] |
| - | [[Category: | + | [[Category: Beta/alpha barrel]] |
| - | [[Category: | + | [[Category: Kdo]] |
| - | [[Category: | + | [[Category: Kdo8p]] |
| - | [[Category: | + | [[Category: Kdo8p]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:04:16 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 18:04, 2 May 2008
Aquifex aeolicus KDO8P synthase in complex with API and Cadmium
Overview
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.
About this Structure
1JCX 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 Page seeded by OCA on Fri May 2 21:04:16 2008
