Title
Molecular dynamics simulations give insight into d-glucose dioxidation at C2 and C3 by Agaricus meleagris pyranose dehydrogenase.
Abstract
The flavin-dependent sugar oxidoreductase pyranose dehydrogenase (PDH) from the plant litter-degrading fungus Agaricus meleagris oxidizes D-glucose (GLC) efficiently at positions C2 and C3. The closely related pyranose 2-oxidase (P2O) from Trametes multicolor oxidizes GLC only at position C2. Consequently, the electron output per molecule GLC is twofold for PDH compared to P2O making it a promising catalyst for bio-electrochemistry or for introducing novel carbonyl functionalities into sugars. The aim of this study was to rationalize the mechanism of GLC dioxidation employing molecular dynamics simulations of GLC-PDH interactions. Shape complementarity through nonpolar van der Waals interactions was identified as the main driving force for GLC binding. Together with a very diverse hydrogen-bonding pattern, this has the potential to explain the experimentally observed promiscuity of PDH towards different sugars. Based on geometrical analysis, we propose a similar reaction mechanism as in P2O involving a general base proton abstraction, stabilization of the transition state, an alkoxide intermediate, through interaction with a protonated catalytic histidine followed by a hydride transfer to the flavin N5 atom. Our data suggest that the presence of the two potential catalytic bases His-512 and His-556 increases the versatility of the enzyme, by employing the most suitably oriented base depending on the substrate and its orientation in the active site. Our findings corroborate and rationalize the experimentally observed dioxidation of GLC by PDH and its promiscuity towards different sugars.
Year
DOI
Venue
2013
10.1007/s10822-013-9645-7
JOURNAL OF COMPUTER-AIDED MOLECULAR DESIGN
Keywords
Field
DocType
Flavoproteins,Protein-ligand interactions,Reaction mechanism,Enzyme promiscuity,Bioelectrochemistry,GROMOS
Oxidoreductase,Protonation,Dehydrogenase,Pyranose,Computational chemistry,Chemistry,D-Glucose,Stereochemistry,Active site,Enzyme promiscuity,Flavin group
Journal
Volume
Issue
ISSN
27
4
0920-654X
Citations 
PageRank 
References 
3
0.47
3
Authors
4
Name
Order
Citations
PageRank
Michael M. H. Graf141.21
Urban Bren2364.13
Dietmar Haltrich340.88
Chris Oostenbrink429738.41