title: Mössbauer studies of the non-heme iron and cytochrome b559 in a Chlamydomonas reinhardtii PSI- mutant and their interactions with alpha-tocopherol quinone.
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.
authors.affiliation: Institute of Nuclear Physics, ul. Radzikowskiego 152, 31-342 Cracow, Poland.
authors.forename: Kvetoslava
authors.initials: K
authors.lastname: Burda
authors.forename: Jerzy
authors.initials: J
authors.lastname: Kruk
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Borgstädt
authors.forename: Jan
authors.initials: J
authors.lastname: Stanek
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Strzałka
authors.forename: Georg H
authors.initials: GH
authors.lastname: Schmid
authors.forename: Olaf
authors.initials: O
authors.lastname: Kruse
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000737:chemistry* / Q000235:genetics; D003573:Cytochrome b Group / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D015151:Immunoblotting; D007501:Iron / Q000737:chemistry*; D007503:Iron Isotopes; D008956:Models, Chemical; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000235:genetics; D045332:Photosystem II Protein Complex; D015204:Spectroscopy, Mossbauer; D013696:Temperature; D020524:Thylakoids / Q000737:chemistry; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000737:chemistry*
chemical_list: D003573:Cytochrome b Group; D007503:Iron Isotopes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D014810:Vitamin E; D006418:Heme; C002421:tocopherylquinone; C019313:cytochrome b559; D007501:Iron