Sökning: id:"swepub:oai:DiVA.org:uu-140640" >
Metalloradical EPR ...
Metalloradical EPR Signals from the Y-Z center dot S-State Intermediates in Photosystem II
-
- Havelius, Kajsa G. V. (författare)
- Uppsala universitet,Molekylär biomimetik
-
- Sjöholm, Johannes (författare)
- Uppsala universitet,Molekylär biomimetik
-
- Ho, Felix M. (författare)
- Uppsala universitet,Molekylär biomimetik
-
visa fler...
-
- Mamedov, Fikret (författare)
- Uppsala universitet,Molekylär biomimetik
-
- Styring, Stenbjörn (författare)
- Uppsala universitet,Molekylär biomimetik
-
visa färre...
-
(creator_code:org_t)
- 2009-11-19
- 2010
- Engelska.
-
Ingår i: Applied Magnetic Resonance. - : Springer Science and Business Media LLC. - 0937-9347 .- 1613-7507. ; 37:1-4, s. 151-176
- Relaterad länk:
-
https://urn.kb.se/re...
-
visa fler...
-
https://doi.org/10.1...
-
visa färre...
Abstract
Ämnesord
Stäng
- The redox-active tyrosine residue (Y-Z) plays a crucial role in the mechanism of the water oxidation. Metalloradical electron paramagnetic resonance (EPR) signals reflecting the light-induced Y-Z center dot in magnetic interaction with the CaMn4-cluster in the particular S-state, Y-Z center dot S-X intermediates, have been found in intact photosystem II. These so-called split EPR signals are induced by illumination at cryogenic temperatures and provide means to both study the otherwise transient Y-Z center dot and to probe the S-states with EPR spectroscopy. The illumination used for signal induction grouped the observed split EPR signals in two categories: (i) Y-Z in the lower S-states was oxidized by P680(+) formed via charge separation, while (ii) Y-Z in the higher S-states was oxidized by an excited, highly oxidizing Mn species. Applied mechanistic studies of the Y-Z center dot S-X intermediates in the different S-states are reviewed and compared to investigations in photosystem II at physiological temperature. Addition of methanol induced S-state characteristic changes in the split signals' formation which reflect changes in the magnetic coupling within the CaMn4-cluster due to methanol binding. The pH titration of the split EPR signals, on the other hand, could probe the proton-coupled electron transfer properties of the Y-Z oxidation. The apparent pK (a)s found for decreased split signal induction were interpreted in the fate of the phenol proton.
Ämnesord
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
Nyckelord
- Chemistry
- Kemi
Publikations- och innehållstyp
- ref (ämneskategori)
- for (ämneskategori)
Hitta via bibliotek
Till lärosätets databas