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A hydrogen-atom abstraction model for the function of Y-Z in photosynthetic oxygen evolution

Hoganson, C W; Tang, X S; Tommos, C; Warncke, K; Babcock, G T; Diner, B A; McCracken, J; Styring, Stenbjörn LU and Lydakis Simantiris, C W (1995) In Photosynthesis Research 46(1-2). p.177-184
Abstract
Recent magnetic-resonance work on Y-Z suggests that this species exhibits considerable motional flexibility in its functional site and that its phenol oxygen is not involved in a well-ordered hydrogen-bond interaction (Tang et al., submitted; Tommos et al., in press). Both of these observations are inconsistent with a simple electron-transfer function for this radical in photosynthetic water oxidation. By considering the roles of catalytically active amino acid radicals in other enzymes and recent data on the water-oxidation process in Photosystem II, we rationalize these observations by suggesting that Y-Z functions to abstract hydrogen atoms from aquo- and hydroxy-bound manganese ions in the (Mn)(4) cluster on each S-state transition.... (More)
Recent magnetic-resonance work on Y-Z suggests that this species exhibits considerable motional flexibility in its functional site and that its phenol oxygen is not involved in a well-ordered hydrogen-bond interaction (Tang et al., submitted; Tommos et al., in press). Both of these observations are inconsistent with a simple electron-transfer function for this radical in photosynthetic water oxidation. By considering the roles of catalytically active amino acid radicals in other enzymes and recent data on the water-oxidation process in Photosystem II, we rationalize these observations by suggesting that Y-Z functions to abstract hydrogen atoms from aquo- and hydroxy-bound manganese ions in the (Mn)(4) cluster on each S-state transition. The hydrogen-atom abstraction process may occur either by sequential or concerted kinetic pathways. Within this model, the (Mn)(4)/Y-Z center forms a single catalytic center that comprises the Oxygen Evolving Complex in Photosystem II. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
electron paramagnetic resonance, manganese cluster, oxygen evolution, oxygen evolving complex, Photosystem II, proton transfer, tyrosine radical, water oxidation
in
Photosynthesis Research
volume
46
issue
1-2
pages
177 - 184
publisher
Springer
external identifiers
  • scopus:0000332870
ISSN
0166-8595
DOI
10.1007/BF00020428
language
English
LU publication?
yes
id
23f38ea0-3096-4d0a-b1e3-54d713bfcc4f (old id 127060)
date added to LUP
2007-07-05 14:14:42
date last changed
2017-01-01 07:02:08
@article{23f38ea0-3096-4d0a-b1e3-54d713bfcc4f,
  abstract     = {Recent magnetic-resonance work on Y-Z suggests that this species exhibits considerable motional flexibility in its functional site and that its phenol oxygen is not involved in a well-ordered hydrogen-bond interaction (Tang et al., submitted; Tommos et al., in press). Both of these observations are inconsistent with a simple electron-transfer function for this radical in photosynthetic water oxidation. By considering the roles of catalytically active amino acid radicals in other enzymes and recent data on the water-oxidation process in Photosystem II, we rationalize these observations by suggesting that Y-Z functions to abstract hydrogen atoms from aquo- and hydroxy-bound manganese ions in the (Mn)(4) cluster on each S-state transition. The hydrogen-atom abstraction process may occur either by sequential or concerted kinetic pathways. Within this model, the (Mn)(4)/Y-Z center forms a single catalytic center that comprises the Oxygen Evolving Complex in Photosystem II.},
  author       = {Hoganson, C W and Tang, X S and Tommos, C and Warncke, K and Babcock, G T and Diner, B A and McCracken, J and Styring, Stenbjörn and Lydakis Simantiris, C W},
  issn         = {0166-8595},
  keyword      = {electron paramagnetic resonance,manganese cluster,oxygen evolution,oxygen evolving complex,Photosystem II,proton transfer,tyrosine radical,water oxidation},
  language     = {eng},
  number       = {1-2},
  pages        = {177--184},
  publisher    = {Springer},
  series       = {Photosynthesis Research},
  title        = {A hydrogen-atom abstraction model for the function of Y-Z in photosynthetic oxygen evolution},
  url          = {http://dx.doi.org/10.1007/BF00020428},
  volume       = {46},
  year         = {1995},
}