Article

Mössbauer studies of the non-heme iron and cytochrome b559 in a Chlamydomonas reinhardtii PSI- mutant and their interactions with alpha-tocopherol quinone.

Institute of Nuclear Physics, ul. Radzikowskiego 152, 31-342 Cracow, Poland.
FEBS Letters (impact factor: 3.54). 02/2003; 535(1-3):159-65. pp.159-65
Source: PubMed

ABSTRACT Spin and valence states of the non-heme iron and the heme iron of cytochrome b559, as well as their interactions with alpha-tocopherol quinone (alpha-TQ) in photosystem II (PSII) thylakoid membranes prepared from the Chlamydomonas reinhardtii PSI- mutant have been studied using Mössbauer spectroscopy. Both of the iron atoms are in low spin ferrous states. The Debye temperature of the non-heme is 194 K and of the heme iron is 182 K. The treatment of alpha-TQ does not change the spin and the valence states of the non-heme iron but enhances the covalence of its bonds. alpha-TQ oxidizes the heme iron into the high spin Fe3+ state. A possible role of the non-heme iron and alpha-TQ in electron flow through the PSII is discussed.

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Keywords

alpha-tocopherol quinone
 
alpha-TQ
 
bonds
 
Chlamydomonas reinhardtii PSI- mutant
 
covalence
 
cytochrome b559
 
Debye temperature
 
ferrous states
 
heme iron
 
iron atoms
 
Mössbauer spectroscopy
 
non-heme iron
 
photosystem II
 
possible role
 
PSII
 
Spin
 
spin Fe3+ state
 
valence states