English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  The first tyrosyl radical intermediate formed in the S2–S3 transition of photosystem II

Retegan, M., Cox, N., Lubitz, W., Neese, F., & Pantazis, D. A. (2014). The first tyrosyl radical intermediate formed in the S2–S3 transition of photosystem II. Physical Chemistry Chemical Physics, 16(24), 11901-11910. doi:10.1039/C4CP00696H.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Retegan, Marius1, Author              
Cox, Nicholas2, Author              
Lubitz, Wolfgang2, Author              
Neese, Frank1, Author              
Pantazis, Dimitrios A.1, Author              
Affiliations:
1Research Department Neese, Max Planck Institute for Chemical Energy Conversion, Max Planck Society, ou_3023886              
2Research Department Lubitz, Max Planck Institute for Chemical Energy Conversion, Max Planck Society, ou_3023873              

Content

show
hide
Free keywords: -
 Abstract: The EPR “split signals” represent key intermediates of the S-state cycle where the redox active D1-Tyr161 (YZ) has been oxidized by the reaction center of the photosystem II enzyme to its tyrosyl radical form, but the successive oxidation of the Mn4CaO5 cluster has not yet occurred (SiYZ˙). Here we focus on the S2YZ˙ state, which is formed en route to the final metastable state of the catalyst, the S3 state, the state which immediately precedes O–O bond formation. Quantum chemical calculations demonstrate that both isomeric forms of the S2 state, the open and closed cubane isomers, can form states with an oxidized YZ˙ residue without prior deprotonation of the Mn4CaO5 cluster. The two forms are expected to lie close in energy and retain the electronic structure and magnetic topology of the corresponding S2 state of the inorganic core. As expected, tyrosine oxidation results in a proton shift towards His190. Analysis of the electronic rearrangements that occur upon formation of the tyrosyl radical suggests that a likely next step in the catalytic cycle is the deprotonation of a terminal water ligand (W1) of the Mn4CaO5 cluster. Diamagnetic metal ion substitution is used in our calculations to obtain the molecular g-tensor of YZ˙. It is known that the gx value is a sensitive probe not only of the extent of the proton shift between the tyrosine–histidine pair, but also of the polarization environment of the tyrosine, especially about the phenolic oxygen. It is shown for PSII that this environment is determined by the Ca2+ ion, which locates two water molecules about the phenoxyl oxygen, indirectly modulating the oxidation potential of YZ.

Details

show
hide
Language(s): eng - English
 Dates: 2014-02-172014-04-032014-04-28
 Publication Status: Published in print
 Pages: 10
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1039/C4CP00696H
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Physical Chemistry Chemical Physics
  Abbreviation : Phys. Chem. Chem. Phys.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Cambridge, England : Royal Society of Chemistry
Pages: - Volume / Issue: 16 (24) Sequence Number: - Start / End Page: 11901 - 11910 Identifier: ISSN: 1463-9076
CoNE: https://pure.mpg.de/cone/journals/resource/954925272413_1