1duv
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1duv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1duv, resolution 1.7Å" /> '''CRYSTAL STRUCTURE OF ...)
Next diff →
Revision as of 11:29, 20 November 2007
|
CRYSTAL STRUCTURE OF E. COLI ORNITHINE TRANSCARBAMOYLASE COMPLEXED WITH NDELTA-L-ORNITHINE-DIAMINOPHOSPHINYL-N-SULPHONIC ACID (PSORN)
Overview
The crystal structure is reported at 1.8 A resolution of Escherichia coli, ornithine transcarbamoylase in complex with the active derivative of, phaseolotoxin from Pseudomonas syringae pv. phaseolicola, N(delta)-(N'-sulfodiaminophosphinyl)-l-ornithine. Electron density reveals, that the complex is not a covalent adduct as previously thought. Kinetic, data confirm that N(delta)-(N'-sulfodiaminophosphinyl)-l-ornithine, exhibits reversible inhibition with a half-life in the order of, approximately 22 h and a dissociation constant of K(D) = 1.6 x 10(-12) m, at 37 degrees C and pH 8.0. Observed hydrogen bonding about the chiral, tetrahedral phosphorus of the inhibitor is consistent only with the, presence of the R enantiomer. A strong interaction is also observed, between Arg(57) Nepsilon and the P-N-S bridging nitrogen indicating that, imino tautomers of N(delta)-(N'-sulfodiaminophosphinyl)-l-ornithine are, present in the bound state. An imino tautomer of, N(delta)-(N'-sulfodiaminophosphinyl)-l-ornithine is structurally analogous, to the proposed reaction transition state. Hence, we propose that, N(delta)-(N'-sulfodiaminophosphinyl)-l-ornithine, with its three unique, N-P bonds, represents a true transition state analogue for ornithine, transcarbamoylases, consistent with the tight binding kinetics observed.
About this Structure
1DUV is a Single protein structure of sequence from Escherichia coli with PSQ and MPD as ligands. Active as Ornithine carbamoyltransferase, with EC number 2.1.3.3 Full crystallographic information is available from OCA.
Reference
Mechanism of inactivation of ornithine transcarbamoylase by Ndelta -(N'-Sulfodiaminophosphinyl)-L-ornithine, a true transition state analogue? Crystal structure and implications for catalytic mechanism., Langley DB, Templeton MD, Fields BA, Mitchell RE, Collyer CA, J Biol Chem. 2000 Jun 30;275(26):20012-9. PMID:10747936
Page seeded by OCA on Tue Nov 20 13:36:16 2007
