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2puh
From Proteopedia
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|PDB= 2puh |SIZE=350|CAPTION= <scene name='initialview01'>2puh</scene>, resolution 1.820Å | |PDB= 2puh |SIZE=350|CAPTION= <scene name='initialview01'>2puh</scene>, resolution 1.820Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=HPK:(3E)-2,6-DIOXO-6-PHENYLHEX-3-ENOATE'>HPK</scene>, <scene name='pdbligand=MLI:MALONATE+ION'>MLI</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= bphD ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=36873 Burkholderia xenovorans]) | |GENE= bphD ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=36873 Burkholderia xenovorans]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[2og1|2OG1]], [[1j1i|1J1I]], [[2d0d|2D0D]], [[1c4x|1C4X]], [[1u2e|1U2E]], [[2pu5|2PU5]], [[2pu6|2PU6]], [[2pu7|2PU7]], [[2puj|2PUJ]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2puh FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2puh OCA], [http://www.ebi.ac.uk/pdbsum/2puh PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2puh RCSB]</span> | ||
}} | }} | ||
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[[Category: Bhowmik, S.]] | [[Category: Bhowmik, S.]] | ||
[[Category: Bolin, J T.]] | [[Category: Bolin, J T.]] | ||
| - | [[Category: HPK]] | ||
| - | [[Category: MLI]] | ||
| - | [[Category: NA]] | ||
[[Category: c-c bond hydrolase]] | [[Category: c-c bond hydrolase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:40:50 2008'' |
Revision as of 01:40, 31 March 2008
| |||||||
| , resolution 1.820Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , | ||||||
| Gene: | bphD (Burkholderia xenovorans) | ||||||
| Related: | 2OG1, 1J1I, 2D0D, 1C4X, 1U2E, 2PU5, 2PU6, 2PU7, 2PUJ
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Crystal Structure of the S112A mutant of a C-C hydrolase, BphD from Burkholderia xenovorans LB400, in complex with its substrate HOPDA
Overview
BphD of Burkholderia xenovorans LB400 catalyzes an unusual C-C bond hydrolysis of 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) to afford benzoic acid and 2-hydroxy-2,4-pentadienoic acid (HPD). An enol-keto tautomerization has been proposed to precede hydrolysis via a gem-diol intermediate. The role of the canonical catalytic triad (Ser-112, His-265, Asp-237) in mediating these two half-reactions remains unclear. We previously reported that the BphD-catalyzed hydrolysis of HOPDA (lambda(max) is 434 nm for the free enolate) proceeds via an unidentified intermediate with a red-shifted absorption spectrum (lambda(max) is 492 nm) (Horsman, G. P., Ke, J., Dai, S., Seah, S. Y. K., Bolin, J. T., and Eltis, L. D. (2006) Biochemistry 45, 11071-11086). Here we demonstrate that the S112A variant generates and traps a similar intermediate (lambda(max) is 506 nm) with a similar rate, 1/tau approximately 500 s(-1). The crystal structure of the S112A:HOPDA complex at 1.8-A resolution identified this intermediate as the keto tautomer, (E)-2,6-dioxo-6-phenyl-hex-3-enoate. This keto tautomer did not accumulate in either the H265A or the S112A/H265A double variants, indicating that His-265 catalyzes tautomerization. Consistent with this role, the wild type and S112A enzymes catalyzed tautomerization of the product HPD, whereas H265A variants did not. This study thus identifies a keto intermediate, and demonstrates that the catalytic triad histidine catalyzes the tautomerization half-reaction, expanding the role of this residue from its purely hydrolytic function in other serine hydrolases. Finally, the S112A:HOPDA crystal structure is more consistent with hydrolysis occurring via an acyl-enzyme intermediate than a gem-diol intermediate as solvent molecules have poor access to C6, and the closest ordered water is 7 A away.
About this Structure
2PUH is a Single protein structure of sequence from Burkholderia xenovorans. Full crystallographic information is available from OCA.
Reference
The tautomeric half-reaction of BphD, a C-C bond hydrolase. Kinetic and structural evidence supporting a key role for histidine 265 of the catalytic triad., Horsman GP, Bhowmik S, Seah SY, Kumar P, Bolin JT, Eltis LD, J Biol Chem. 2007 Jul 6;282(27):19894-904. Epub 2007 Apr 18. PMID:17442675
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