The Library
Amine oxidation mediated by n-methyltryptophan oxidase : computational insights into the mechanism, role of active-site residues, and covalent flavin binding
Tools
Karasulu, Bora and Thiel, Walter (2015) Amine oxidation mediated by n-methyltryptophan oxidase : computational insights into the mechanism, role of active-site residues, and covalent flavin binding. ACS Catalysis, 5 (2). pp. 1227-1239. doi:10.1021/cs501694q ISSN 2155-5435.
Research output not available from this repository.
Request-a-Copy directly from author or use local Library Get it For Me service.
Official URL: http://dx.doi.org/10.1021/cs501694q
Abstract
Amine oxidation, a process widely utilized by flavoprotein oxidases, is the rate-determining step in the three-step demethylation of N-methyltryptophan (NMT) catalyzed by N-methyltryptophan oxidase (MTOX), which employs a covalently bound flavin adenine dinucleotide (FAD) as cofactor. For the required transfer of a hydride ion equivalent, three pathways (direct/concerted, radical, and adduct-forming/polar nucleophilic) have been proposed, without a consensus on which one is commonly used by amine oxidases. We combine theoretical pKa analysis, classical molecular dynamics (MD) simulations, and pure quantum mechanics (QM) and hybrid QM/molecular mechanics (QM/MM) calculations to provide molecular-level insights into the catalytic mechanism of NMT oxidation and to analyze the role of MTOX active-site residues and covalent FAD incorporation for NMT binding and oxidation. The QM(B3LYP-D2/6-31G(d))/CHARMM results clearly favor a direct concerted hydride transfer (HT) mechanism involving anionic NMT as the reactive species. On the basis of classical canonical MD simulations and QM/MM calculations of wild-type MTOX and two mutants (K341Q and H263N), we propose that the K341 residue acts as an active-site base and electrostatically, whereas H263 and Tyr249 only support substrate alignment. Covalent FAD binding leads to a more bent isoalloxazine moiety, which facilitates the binding of anionic NMT but increases the catalytic activity of FAD only slightly.
Item Type: | Journal Article | ||||||
---|---|---|---|---|---|---|---|
Divisions: | Faculty of Science, Engineering and Medicine > Science > Chemistry | ||||||
Journal or Publication Title: | ACS Catalysis | ||||||
Publisher: | American Chemical Society | ||||||
ISSN: | 2155-5435 | ||||||
Official Date: | February 2015 | ||||||
Dates: |
|
||||||
Volume: | 5 | ||||||
Number: | 2 | ||||||
Page Range: | pp. 1227-1239 | ||||||
DOI: | 10.1021/cs501694q | ||||||
Status: | Peer Reviewed | ||||||
Publication Status: | Published | ||||||
Access rights to Published version: | Restricted or Subscription Access |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |