Bicarbonate binding to the water-oxidizing complex in the photosystem II. A Fourier transform infrared spectroscopy study

I. Yruela, S. I. Allakhverdiev, J. V. Ibarra, V. V. Klimov

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The light-induced Fourier transform infrared difference (FT-IR) spectrum originating from the donor side of O2-evolving photosystem (PS) II was obtained in non-depleted and CO2-depleted PSII membrane preparations. The observed spectrum free of contributions from the acceptor side signals was achieved by employing 2 mM/18 mM ferri-/ferrocyanide as a redox couple. This spectrum showed main positive bands at 1589 and 1365 cm-1 and negative bands at 1560, 1541, 1522 and 1507 cm-1. CO-depleted PSII preparations showed a quite different spectrum. The main positive and negative bands disappeared after depletion of bicarbonate. The addition of bicarbonate partially restored those bands again. Comparison between difference FT-IR spectra of untreated and bicarbonate-depleted PSII membranes indicated that the positive bands at 1589 and 1365 cm-1 can be assigned to COO- stretching modes from bicarbonate. The higher frequency corresponds to u(as) (COO-) and the lower frequency to u(s) (COO-). 13C-Labeling FT-IR measurements confirmed these findings and also suggested that the negative band at 1560 cm-1 can be ascribed to u(as) (COO-). The data are discussed in the framework of the suggestion that bicarbonate can be a ligand to the Mn-containing water-oxidizing complex of PSII.

Original languageEnglish
Pages (from-to)396-400
Number of pages5
JournalFEBS Letters
Volume425
Issue number3
DOIs
Publication statusPublished - Apr 3 1998

Keywords

  • Bicarbonate
  • Donor side
  • Fourier transform
  • Infrared spectroscopy
  • Photosystem II

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

Fingerprint Dive into the research topics of 'Bicarbonate binding to the water-oxidizing complex in the photosystem II. A Fourier transform infrared spectroscopy study'. Together they form a unique fingerprint.

  • Cite this