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Tyrosyl radicals in enzyme catalysis: Some properties and a focus on photosynthetic water oxidation

Babcock, Gerald T; Espe, M; Hoganson, Curtis; LydakisSimantiris, N; McCracken, Vance J; Shi, W J; Styring, Stenbjörn LU ; Tommos, Cecilia and Warncke, K (1997) In Acta Chemica Scandinavica 51(5). p.533-540
Abstract
Enzymes that require a redox-active amino acid for catalysis or function have emerged as a distinct class of proteins. For the tyrosine-based radical enzymes, we show that the spin-density distribution in the radical follows an odd alternate pattern that is invariant to within 10% across the class. General properties of the radical enzymes are summarized from which we conclude that their essential role in catalysis is to initiate substrate metabolism by hydrogen-atom abstraction. These ideas are extended to the Y-Z and Y-D tyrosines in Photosystem II and a radical-based hydrogen-atom abstraction model for water oxidation is discussed. Differences in rates of oxidation of Y-Z and Y-D by the reaction-center chlorophyll, P680(+), under... (More)
Enzymes that require a redox-active amino acid for catalysis or function have emerged as a distinct class of proteins. For the tyrosine-based radical enzymes, we show that the spin-density distribution in the radical follows an odd alternate pattern that is invariant to within 10% across the class. General properties of the radical enzymes are summarized from which we conclude that their essential role in catalysis is to initiate substrate metabolism by hydrogen-atom abstraction. These ideas are extended to the Y-Z and Y-D tyrosines in Photosystem II and a radical-based hydrogen-atom abstraction model for water oxidation is discussed. Differences in rates of oxidation of Y-Z and Y-D by the reaction-center chlorophyll, P680(+), under various conditions, are considered and rationalized on the basis of changes in reorganization energy induced by the local protein structure and by the presence or absence of the (Mn)(4) cluster that binds substrate water. (Less)
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keywords
HYDROGEN HYPERFINE INTERACTIONS, ELECTRON-TRANSFER REACTIONS, SITE-DIRECTED MUTANTS, PHOTOSYSTEM-II, RIBONUCLEOTIDE REDUCTASE, RESONANCE SPECTROSCOPIES, VIBRATIONAL FREQUENCIES, SPIN-DENSITIES, Y-Z, TYROSINE(D)
in
Acta Chemica Scandinavica
volume
51
issue
5
pages
533 - 540
publisher
Munksgaard International Publishers
external identifiers
  • scopus:0031136628
ISSN
0904-213X
language
English
LU publication?
yes
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839e5758-855b-4a15-bcb1-2073c763a6fb (old id 126119)
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http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=9190041&dopt=Abstract
date added to LUP
2007-07-04 11:02:52
date last changed
2017-01-01 07:20:06
@article{839e5758-855b-4a15-bcb1-2073c763a6fb,
  abstract     = {Enzymes that require a redox-active amino acid for catalysis or function have emerged as a distinct class of proteins. For the tyrosine-based radical enzymes, we show that the spin-density distribution in the radical follows an odd alternate pattern that is invariant to within 10% across the class. General properties of the radical enzymes are summarized from which we conclude that their essential role in catalysis is to initiate substrate metabolism by hydrogen-atom abstraction. These ideas are extended to the Y-Z and Y-D tyrosines in Photosystem II and a radical-based hydrogen-atom abstraction model for water oxidation is discussed. Differences in rates of oxidation of Y-Z and Y-D by the reaction-center chlorophyll, P680(+), under various conditions, are considered and rationalized on the basis of changes in reorganization energy induced by the local protein structure and by the presence or absence of the (Mn)(4) cluster that binds substrate water.},
  author       = {Babcock, Gerald T and Espe, M and Hoganson, Curtis and LydakisSimantiris, N and McCracken, Vance J and Shi, W J and Styring, Stenbjörn and Tommos, Cecilia and Warncke, K},
  issn         = {0904-213X},
  keyword      = {HYDROGEN HYPERFINE INTERACTIONS,ELECTRON-TRANSFER REACTIONS,SITE-DIRECTED MUTANTS,PHOTOSYSTEM-II,RIBONUCLEOTIDE REDUCTASE,RESONANCE SPECTROSCOPIES,VIBRATIONAL FREQUENCIES,SPIN-DENSITIES,Y-Z,TYROSINE(D)},
  language     = {eng},
  number       = {5},
  pages        = {533--540},
  publisher    = {Munksgaard International Publishers},
  series       = {Acta Chemica Scandinavica},
  title        = {Tyrosyl radicals in enzyme catalysis: Some properties and a focus on photosynthetic water oxidation},
  volume       = {51},
  year         = {1997},
}