2oqe
From Proteopedia
Crystal Structure of Hansenula polymorpha amine oxidase in complex with Xe to 1.6 Angstroms
Overview
The accessibility of large substrates to buried enzymatic active sites is dependent upon the utilization of proteinaceous channels. The necessity of these channels in the case of small substrates is questionable because diffusion through the protein matrix is often assumed. Copper amine oxidases contain a buried protein-derived quinone cofactor and a mononuclear copper center that catalyze the conversion of two substrates, primary amines and molecular oxygen, to aldehydes and hydrogen peroxide, respectively. The nature of molecular oxygen migration to the active site in the enzyme from Hansenula polymorpha is explored using a combination of kinetic, x-ray crystallographic, and computational approaches. A crystal structure of H. polymorpha amine oxidase in complex with xenon gas, which serves as an experimental probe for molecular oxygen binding sites, reveals buried regions of the enzyme suitable for transient molecular oxygen occupation. Calculated O(2) free energy maps using copper amine oxidase crystal structures in the absence of xenon correspond well with later experimentally observed xenon sites in these systems, and allow the visualization of O(2) migration routes of differing probabilities within the protein matrix. Site-directed mutagenesis designed to block individual routes has little effect on overall k(cat)/K(m) (O(2)), supporting multiple dynamic pathways for molecular oxygen to reach the active site.
About this Structure
2OQE is a Protein complex structure of sequences from [1] and Pichia angusta. Full crystallographic information is available from OCA.
Reference
Exploring molecular oxygen pathways in Hansenula polymorpha copper-containing amine oxidase., Johnson BJ, Cohen J, Welford RW, Pearson AR, Schulten K, Klinman JP, Wilmot CM, J Biol Chem. 2007 Jun 15;282(24):17767-76. Epub 2007 Apr 4. PMID:17409383 Page seeded by OCA on Sun May 4 11:26:58 2008
