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

• Published in: FEBS letters 2003-01, Vol.535 (1-3), p.159-165
• Main Authors: Burda, Květoslava, Kruk, Jerzy, Borgstädt, Rüdiger, Stanek, Jan, Strzałka, Kazimierz, Schmid, Georg H., Kruse, Olaf
• Format: Article
• Language: English
• Subjects: Animals; Chlamydomonas reinhardtii - chemistry; Chlamydomonas reinhardtii - genetics; Cytochrome b Group - chemistry; Cytochrome b559; Heme - chemistry; Immunoblotting; Iron - chemistry; Iron Isotopes; Models, Chemical; Non-heme iron; Photosynthetic Reaction Center Complex Proteins - chemistry; Photosynthetic Reaction Center Complex Proteins - genetics; Photosystem II; Photosystem II Protein Complex; Spectroscopy, Mossbauer; Temperature; Thylakoids - chemistry; Vitamin E - analogs & derivatives; Vitamin E - chemistry; α-Tocopherol quinone
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(02)03895-4

Spin and valence states of the non-heme iron and the heme iron of cytochrome b559, as well as their interactions with α-tocopherol quinone (α-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 α-TQ does not change the spin and the valence states of the non-heme iron but enhances the covalence of its bonds. α-TQ oxidizes the heme iron into the high spin Fe3+ state. A possible role of the non-heme iron and α-TQ in electron flow through the PSII is discussed.