Proton release upon oxidation of tyrosine in reaction centers from Rhodobacter sphaeroides

L. Kálmán, J. C. Williams, James Paul Allen

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Markedly different light-induced protonational changes were measured in two reaction center mutants of Rhodobacter sphaeroides. A quadruple mutant containing alterations, at residues L131, M160, M197, and M210, that elevate the midpoint potential of the bacteriochlorophyll dimer was compared to the YM mutant, which contains these alterations plus a tyrosine at M164 serving as a secondary electron donor [Kálmán et al., Nature 402 (1999) 696]. In the quadruple mutant, a proton uptake of 0.1-0.3 H+/reaction center between pH 6 and 10 resulted from formation of the oxidized bacteriochlorophyll donor and reduced primary quinone. In the YM mutant, a maximal proton release of -0.5 H+/reaction center at pH 8 was attributed to formation of the tyrosyl radical and modeled using electrostatic and direct proton-releasing mechanisms.

Original languageEnglish
Pages (from-to)193-198
Number of pages6
JournalFEBS Letters
Volume545
Issue number2-3
DOIs
Publication statusPublished - Jun 19 2003

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Rhodobacter sphaeroides
Bacteriochlorophylls
Tyrosine
Protons
Oxidation
Static Electricity
Dimers
Electrostatics
Electrons
Light

Keywords

  • Amino acid radical
  • Electron transfer
  • Photosynthesis
  • Photosystem II
  • Proton transfer

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

Proton release upon oxidation of tyrosine in reaction centers from Rhodobacter sphaeroides. / Kálmán, L.; Williams, J. C.; Allen, James Paul.

In: FEBS Letters, Vol. 545, No. 2-3, 19.06.2003, p. 193-198.

Research output: Contribution to journalArticle

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