1phh
|
CRYSTAL STRUCTURE OF P-HYDROXYBENZOATE HYDROXYLASE COMPLEXED WITH ITS REACTION PRODUCT 3,4-DIHYDROXYBENZOATE
OverviewOverview
Crystals of the flavin-containing enzyme p-hydroxybenzoate hydroxylase, (PHBHase) complexed with its reaction product were investigated in order, to obtain insight into the catalytic cycle of this enzyme involving two, substrates and two cofactors. PHBHase was crystallized initially with its, substrate, p-hydroxybenzoate and the substrate was then converted into the, product 3,4-dihydroxybenzoate by allowing the catalytic reaction to, proceed in the crystals. In addition, crystals were soaked in mother, liquor containing a high concentration of this product. Data up to 2.3 A, (1 A = 0.1 nm) were collected by the oscillation method and the structure, of the enzyme product complex was refined by alternate restrained, least-squares procedures and model building by computer graphics, techniques. A total of 273 solvent molecules could be located, four of, them being presumably sulfate ions. The R-factor for 14,339 reflections, between 6.0 A and 2.3 A is 19.3%. The 3-hydroxyl group of the product, introduced by the enzyme is clearly visible in the electron density, showing unambiguously which carbon atom of the substrate is hydroxylated., A clear picture of the hydroxylation site is obtained. The plane of the, product is rotated 21 degrees with respect to the plane of the substrate, in the current model of enzyme-substrate complex. The 4-hydroxyl group of, the product is hydrogen bonded to the hydroxyl group of Tyr201, its, carboxyl group is interacting with the side-chains of Tyr222, Arg214 and, Ser212, while the newly introduced 3-hydroxyl group makes a hydrogen bond, with the backbone carbonyl oxygen of Pro293.
About this StructureAbout this Structure
1PHH is a Single protein structure of sequence from Pseudomonas fluorescens with FAD and DHB as ligands. Active as 4-hydroxybenzoate 3-monooxygenase, with EC number 1.14.13.2 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of p-hydroxybenzoate hydroxylase complexed with its reaction product 3,4-dihydroxybenzoate., Schreuder HA, van der Laan JM, Hol WG, Drenth J, J Mol Biol. 1988 Feb 20;199(4):637-48. PMID:3351945
Page seeded by OCA on Tue Nov 20 23:49:09 2007