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- | [[Image:1w8s.gif|left|200px]] | + | {{Seed}} |
| + | [[Image:1w8s.png|left|200px]] |
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| {{STRUCTURE_1w8s| PDB=1w8s | SCENE= }} | | {{STRUCTURE_1w8s| PDB=1w8s | SCENE= }} |
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- | '''THE MECHANISM OF THE SCHIFF BASE FORMING FRUCTOSE-1,6-BISPHOSPHATE ALDOLASE: STRUCTURAL ANALYSIS OF REACTION INTERMEDIATES'''
| + | ===THE MECHANISM OF THE SCHIFF BASE FORMING FRUCTOSE-1,6-BISPHOSPHATE ALDOLASE: STRUCTURAL ANALYSIS OF REACTION INTERMEDIATES=== |
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- | ==Overview==
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- | The glycolytic enzyme fructose-1,6-bisphosphate aldolase (FBPA) catalyzes the reversible cleavage of fructose 1,6-bisphosphate to glyceraldehyde 3-phosphate and dihydroxyacetone phosphate. Catalysis of Schiff base forming class I FBPA relies on a number of intermediates covalently bound to the catalytic lysine. Using active site mutants of FBPA I from Thermoproteus tenax, we have solved the crystal structures of the enzyme covalently bound to the carbinolamine of the substrate fructose 1,6-bisphosphate and noncovalently bound to the cyclic form of the substrate. The structures, determined at a resolution of 1.9 A and refined to crystallographic R factors of 0.148 and 0.149, respectively, represent the first view of any FBPA I in these two stages of the reaction pathway and allow detailed analysis of the roles of active site residues in catalysis. The active site geometry of the Tyr146Phe FBPA variant with the carbinolamine intermediate supports the notion that in the archaeal FBPA I Tyr146 is the proton donor catalyzing the conversion between the carbinolamine and Schiff base. Our structural analysis furthermore indicates that Glu187 is the proton donor in the eukaryotic FBPA I, whereas an aspartic acid, conserved in all FBPA I enzymes, is in a perfect position to be the general base facilitating carbon-carbon cleavage. The crystal structure of the Trp144Glu, Tyr146Phe double-mutant substrate complex represents the first example where the cyclic form of beta-fructose 1,6-bisphosphate is noncovalently bound to FBPA I. The structure thus allows for the first time the catalytic mechanism of ring opening to be unraveled. | + | The line below this paragraph, {{ABSTRACT_PUBMED_15766250}}, adds the Publication Abstract to the page |
| + | (as it appears on PubMed at http://www.pubmed.gov), where 15766250 is the PubMed ID number. |
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| + | {{ABSTRACT_PUBMED_15766250}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Reaction intermediate]] | | [[Category: Reaction intermediate]] |
| [[Category: Tim barrel]] | | [[Category: Tim barrel]] |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:18:56 2008'' | + | |
| + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 11:03:26 2008'' |
Revision as of 08:03, 28 July 2008
Template:STRUCTURE 1w8s
THE MECHANISM OF THE SCHIFF BASE FORMING FRUCTOSE-1,6-BISPHOSPHATE ALDOLASE: STRUCTURAL ANALYSIS OF REACTION INTERMEDIATES
Template:ABSTRACT PUBMED 15766250
About this Structure
1W8S is a Single protein structure of sequence from Thermoproteus tenax. Full crystallographic information is available from OCA.
Reference
Mechanism of the Schiff base forming fructose-1,6-bisphosphate aldolase: structural analysis of reaction intermediates., Lorentzen E, Siebers B, Hensel R, Pohl E, Biochemistry. 2005 Mar 22;44(11):4222-9. PMID:15766250
Page seeded by OCA on Mon Jul 28 11:03:26 2008