This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1pdh
From Proteopedia
| |||||||
| , resolution 2.1Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Activity: | 4-hydroxybenzoate 3-monooxygenase, with EC number 1.14.13.2 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURE OF P-HYDROXYBENZOATE HYDROXYLASE RECONSTITUTED WITH THE MODIFIED FAD PRESENT IN ALCOHOL OXIDASE FROM METHYLOTROPHIC YEASTS: EVIDENCE FOR AN ARABINOFLAVIN
Overview
The flavin prosthetic group (FAD) of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens was replaced by a stereochemical analog, which is spontaneously formed from natural FAD in alcohol oxidases from methylotrophic yeasts. Reconstitution of p-hydroxybenzoate hydroxylase from apoprotein and modified FAD is a rapid process complete within seconds. Crystals of the enzyme-substrate complex of modified FAD-containing p-hydroxybenzoate hydroxylase diffract to 2.1 A resolution. The crystal structure provides direct evidence for the presence of an arabityl sugar chain in the modified form of FAD. The isoalloxazine ring of the arabinoflavin adenine dinucleotide (a-FAD) is located in a cleft outside the active site as recently observed in several other p-hydroxybenzoate hydroxylase complexes. Like the native enzyme, a-FAD-containing p-hydroxybenzoate hydroxylase preferentially binds the phenolate form of the substrate (pKo = 7.2). The substrate acts as an effector highly stimulating the rate of enzyme reduction by NADPH (kred > 500 s-1). The oxidative part of the catalytic cycle of a-FAD-containing p-hydroxybenzoate hydroxylase differs from native enzyme. Partial uncoupling of hydroxylation results in the formation of about 0.3 mol of 3,4-dihydroxybenzoate and 0.7 mol of hydrogen peroxide per mol NADPH oxidized. It is proposed that flavin motion in p-hydroxybenzoate hydroxylase is important for efficient reduction and that the flavin "out" conformation is associated with the oxidase activity.
About this Structure
1PDH is a Single protein structure of sequence from Pseudomonas fluorescens. Full crystallographic information is available from OCA.
Reference
Crystal structure of p-hydroxybenzoate hydroxylase reconstituted with the modified FAD present in alcohol oxidase from methylotrophic yeasts: evidence for an arabinoflavin., van Berkel WJ, Eppink MH, Schreuder HA, Protein Sci. 1994 Dec;3(12):2245-53. PMID:7756982
Page seeded by OCA on Thu Mar 20 13:22:57 2008
