Ab initio g-tensor calculations of the thioether substituted tyrosyl radical in galactose oxidase

Citation
M. Engstrom et al., Ab initio g-tensor calculations of the thioether substituted tyrosyl radical in galactose oxidase, CHEM P LETT, 319(3-4), 2000, pp. 191-196
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS LETTERS
ISSN journal
0009-2614 → ACNP
Volume
319
Issue
3-4
Year of publication
2000
Pages
191 - 196
Database
ISI
SICI code
0009-2614(20000317)319:3-4<191:AIGCOT>2.0.ZU;2-R
Abstract
The tyrosyl radical in galactose oxidase is covalently cross-linked to a ne ighboring cysteine residue through a thioether bond. The role of this sulfu r cross-link has been discussed ever since the crystal structure of the enz yme was solved. In the present work, the ab initio multiconfigurational lin ear response method is applied to calculate the g-tensor of unsubstituted a nd thioether substituted phenoxyl radicals. In contrast to some previous in terpretations, but in agreement with recent EPR measurements, we find that the sulfur substitution induces only minor shifts in the g-tensor component s. The spin distribution retains the odd-alternant pattern of the unsubstit uted radical and only a small amount of spin is localized to the sulfur cen ter. (C) 2000 Elsevier Science B.V. All rights reserved.