Flash-induced proton transfer in photosynthetic bacteria

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

A proton electrochemical potential across the membranes of photosynthetic purple bacteria is established by a light-driven proton pump mechanism: the absorbed light in the reaction center initiates electron transfer which is coupled to the vectorial displacement of protons from the cytoplasm to the periplasm. The stoichiometry and kinetics of proton binding and release can be tracked directly by electric (glass electrodes), spectrophotometric (pH indicator dyes) and conductimetric techniques. The primary step in the formation of the transmembrane chemiosmotic potential is the uptake of two protons by the doubly reduced secondary quinone in the reaction center and the subsequent exchange of hydroquinol for quinone from the membrane quinone-pool. However, the proton binding associated with singly reduced promary and/or secondary quinones of the reaction center is substoichiometric, pH-dependent and its rate is electrostatically enhanced but not diffusion limited. Molecular details of protonation are discussed based on the crystallographic structure of the reaction center of purple bacteria Rb. sphaeroides and Rps. viridis, structure-based molecular (electrostatic) calculations and mutagenesis directed at protonatable amino acids supposed to be involved in proton conduction pathways.

Original languageEnglish
Pages (from-to)1-17
Number of pages17
JournalPhotosynthesis Research
Volume37
Issue number1
DOIs
Publication statusPublished - Jul 1993

Fingerprint

photosynthetic bacteria
Proton transfer
protons
Protons
Bacteria
quinones
Proteobacteria
Membrane Potentials
Membranes
Light
Proton Pumps
Periplasm
Quinones
Mutagenesis
proton pump
Protonation
stoichiometry
Molecular Structure
Static Electricity
membrane potential

Keywords

  • bacterial photosynthesis
  • kinetics
  • proton binding
  • reaction center
  • stoichiometry

ASJC Scopus subject areas

  • Plant Science

Cite this

Flash-induced proton transfer in photosynthetic bacteria. / Maróti, P.

In: Photosynthesis Research, Vol. 37, No. 1, 07.1993, p. 1-17.

Research output: Contribution to journalArticle

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