2fm7: Difference between revisions
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[[Image:2fm7.gif|left|200px]] | [[Image:2fm7.gif|left|200px]] | ||
'''Evolution of Enzymatic Activity in the Tautomerase Superfamily: Mechanistic and Structural Consequences of the L8R Mutation in 4-Oxalocrotonate Tautomerase''' | {{Structure | ||
|PDB= 2fm7 |SIZE=350|CAPTION= <scene name='initialview01'>2fm7</scene>, resolution 2.80Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=CL:CHLORIDE ION'>CL</scene> | |||
|ACTIVITY= | |||
|GENE= xylH ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=303 Pseudomonas putida]) | |||
}} | |||
'''Evolution of Enzymatic Activity in the Tautomerase Superfamily: Mechanistic and Structural Consequences of the L8R Mutation in 4-Oxalocrotonate Tautomerase''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
2FM7 is a [ | 2FM7 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FM7 OCA]. | ||
==Reference== | ==Reference== | ||
Evolution of enzymatic activity in the tautomerase superfamily: mechanistic and structural consequences of the L8R mutation in 4-oxalocrotonate tautomerase., Poelarends GJ, Almrud JJ, Serrano H, Darty JE, Johnson WH Jr, Hackert ML, Whitman CP, Biochemistry. 2006 Jun 27;45(25):7700-8. PMID:[http:// | Evolution of enzymatic activity in the tautomerase superfamily: mechanistic and structural consequences of the L8R mutation in 4-oxalocrotonate tautomerase., Poelarends GJ, Almrud JJ, Serrano H, Darty JE, Johnson WH Jr, Hackert ML, Whitman CP, Biochemistry. 2006 Jun 27;45(25):7700-8. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16784221 16784221] | ||
[[Category: Pseudomonas putida]] | [[Category: Pseudomonas putida]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: 4-oxalocrotonate; tautomerase; 4-ot; homo-hexamer; dehalogenase; mutant; l8r]] | [[Category: 4-oxalocrotonate; tautomerase; 4-ot; homo-hexamer; dehalogenase; mutant; l8r]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 16:54:07 2008'' | ||
Revision as of 17:54, 20 March 2008
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| , resolution 2.80Å | |||||||
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| Ligands: | |||||||
| Gene: | xylH (Pseudomonas putida) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Evolution of Enzymatic Activity in the Tautomerase Superfamily: Mechanistic and Structural Consequences of the L8R Mutation in 4-Oxalocrotonate Tautomerase
OverviewOverview
4-Oxalocrotonate tautomerase (4-OT) and trans-3-chloroacrylic acid dehalogenase (CaaD) are members of the tautomerase superfamily, a group of structurally homologous proteins that share a beta-alpha-beta fold and a catalytic amino-terminal proline. 4-OT, from Pseudomonas putida mt-2, catalyzes the conversion of 2-oxo-4-hexenedioate to 2-oxo-3-hexenedioate through the dienol intermediate 2-hydroxymuconate in a catabolic pathway for aromatic hydrocarbons. CaaD, from Pseudomonas pavonaceae 170, catalyzes the hydrolytic dehalogenation of trans-3-chloroacrylate in the trans-1,3-dichloropropene degradation pathway. Both reactions may involve an arginine-stabilized enediolate intermediate, a capability that may partially account for the low-level CaaD activity of 4-OT. Two active-site residues in 4-OT, Leu-8 and Ile-52, have now been mutated to the positionally conserved and catalytic ones in CaaD, alphaArg-8, and alphaGlu-52. The L8R and L8R/I52E mutants show improved CaaD activity (50- and 32-fold increases in k(cat)/K(m), respectively) and diminished 4-OT activity (5- and 1700-fold decreases in k(cat)/K(m), respectively). The increased efficiency of L8R-4-OT for the CaaD reaction stems primarily from an 8.8-fold increase in k(cat), whereas that of the L8R/I52E mutant is due largely to a 23-fold decrease in K(m). The presence of the additional arginine residue in the active site of L8R-4-OT does not alter the pK(a) of the Pro-1 amino group from that measured for the wild type (6.5 +/- 0.1 versus 6.4 +/- 0.2). Moreover, the crystal structure of L8R-4-OT is comparable to that of the wild type. Hence, the enhanced CaaD activity of L8R-4-OT is likely due to the additional arginine residue that can participate in substrate binding and/or stabilization of the putative enediolate intermediate. The results also suggest that the evolution of new functions within the tautomerase superfamily could be quite facile, requiring only a few strategically placed active-site mutations.
About this StructureAbout this Structure
2FM7 is a Single protein structure of sequence from Pseudomonas putida. Full crystallographic information is available from OCA.
ReferenceReference
Evolution of enzymatic activity in the tautomerase superfamily: mechanistic and structural consequences of the L8R mutation in 4-oxalocrotonate tautomerase., Poelarends GJ, Almrud JJ, Serrano H, Darty JE, Johnson WH Jr, Hackert ML, Whitman CP, Biochemistry. 2006 Jun 27;45(25):7700-8. PMID:16784221
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