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The nature of tryptophan radicals involved in the long‐range electron transfer of lignin peroxidase and lignin peroxidase‐like systems: Insights from quantum mechanical/molecular mechanics simulations
Author(s) -
Bernini Caterina,
Pogni Rebecca,
Basosi Riccardo,
Sinicropi Adalgisa
Publication year - 2012
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.24046
Subject(s) - tryptophan , lignin , phanerochaete , chemistry , radical , peroxidase , electron transfer , electron paramagnetic resonance , lignin peroxidase , photochemistry , heme , redox , organic chemistry , biochemistry , enzyme , nuclear magnetic resonance , amino acid , physics
A catalytically active tryptophan radical has been demonstrated to be involved in the long‐range electron transfer to the heme cofactor of lignin peroxidase (LiP) from Phanerochaete chrysosporium although no direct detection by EPR spectroscopy of the tryptophan radical intermediate has been reported to date. An engineering‐based approach has been used to manipulate the microenvironment of the redox‐active tryptophan site in LiP and Coprinus cinereus Peroxidase (CiP), allowing the direct evidence of the tryptophan radical species. In light of the newly available EPR experimental data, we performed a quantum mechanical/molecular mechanics computational study to characterize the tryptophan radicals in the above protein matrices as well as in pristine LiP. The nature of the tryptophan radicals is discussed together with the analysis of their environment with the aim of understanding the different behavior of pristine LiP in comparison with that of LiP and CiP variants. Proteins 2012. © 2012 Wiley Periodicals, Inc.