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

FEBS Lett. 2003 Jan 30;535(1-3):159-65. doi: 10.1016/s0014-5793(02)03895-4.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chlamydomonas reinhardtii / chemistry*
  • Chlamydomonas reinhardtii / genetics
  • Cytochrome b Group / chemistry*
  • Heme / chemistry
  • Immunoblotting
  • Iron / chemistry*
  • Iron Isotopes
  • Models, Chemical
  • Photosynthetic Reaction Center Complex Proteins / chemistry*
  • Photosynthetic Reaction Center Complex Proteins / genetics
  • Photosystem II Protein Complex*
  • Spectroscopy, Mossbauer
  • Temperature
  • Thylakoids / chemistry
  • Vitamin E / analogs & derivatives*
  • Vitamin E / chemistry*

Substances

  • Cytochrome b Group
  • Iron Isotopes
  • Photosynthetic Reaction Center Complex Proteins
  • Photosystem II Protein Complex
  • Vitamin E
  • Heme
  • tocopherylquinone
  • cytochrome b559
  • Iron