M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria

Hélène Cheap, Sophie Bernad, Valérie Derrien, László Gerencsér, Julia Tandori, Pedro de Oliveira, Deborah K. Hanson, P. Maróti, Pierre Sebban

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Bacterial reaction centers use light energy to couple the uptake of protons to the successive semi-reduction of two quinones, namely QA and QB. These molecules are situated symmetrically in regard to a non-heme iron atom. Four histidines and one glutamic acid, M234Glu, constitute the five ligands of this atom. By flash-induced absorption spectroscopy and delayed fluorescence we have studied in the M234EH and M234EL variants the role played by this acidic residue on the energetic balance between the two quinones as well as in proton uptake. Delayed fluorescence from the P+QA - state (P is the primary electron donor) and temperature dependence of the rate of P+QA - charge recombination that are in good agreement show that in the two RC variants, both QA - and QB - are destabilized by about the same free energy amount: respectively ∼ 100 ± 5 meV and 90 ± 5 meV for the M234EH and M234EL variants, as compared to the WT. Importantly, in the M234EH and M234EL variants we observe a collapse of the high pH band (present in the wild-type reaction center) of the proton uptake amplitudes associated with formation of QA - and QB -. This band has recently been shown to be a signature of a collective behaviour of an extended, multi-entry, proton uptake network. M234Glu seems to play a central role in the proton sponge-like system formed by the RC protein.

Original languageEnglish
Pages (from-to)1505-1515
Number of pages11
JournalBBA - Bioenergetics
Volume1787
Issue number12
DOIs
Publication statusPublished - Dec 2009

Fingerprint

Photosynthetic Reaction Center Complex Proteins
Porifera
Protons
Bacteria
Quinones
Fluorescence
Atoms
Fluorescence Spectrometry
Absorption spectroscopy
Histidine
Genetic Recombination
Free energy
Glutamic Acid
Iron
Electrons
Ligands
Light
Molecules
Temperature
Proteins

Keywords

  • Bioenergetics
  • Electron transfer
  • Hydrogen-bond network
  • Photosynthesis
  • Proton transfer
  • Reaction center

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology

Cite this

Cheap, H., Bernad, S., Derrien, V., Gerencsér, L., Tandori, J., de Oliveira, P., ... Sebban, P. (2009). M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria. BBA - Bioenergetics, 1787(12), 1505-1515. https://doi.org/10.1016/j.bbabio.2009.07.004

M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria. / Cheap, Hélène; Bernad, Sophie; Derrien, Valérie; Gerencsér, László; Tandori, Julia; de Oliveira, Pedro; Hanson, Deborah K.; Maróti, P.; Sebban, Pierre.

In: BBA - Bioenergetics, Vol. 1787, No. 12, 12.2009, p. 1505-1515.

Research output: Contribution to journalArticle

Cheap, H, Bernad, S, Derrien, V, Gerencsér, L, Tandori, J, de Oliveira, P, Hanson, DK, Maróti, P & Sebban, P 2009, 'M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria', BBA - Bioenergetics, vol. 1787, no. 12, pp. 1505-1515. https://doi.org/10.1016/j.bbabio.2009.07.004
Cheap H, Bernad S, Derrien V, Gerencsér L, Tandori J, de Oliveira P et al. M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria. BBA - Bioenergetics. 2009 Dec;1787(12):1505-1515. https://doi.org/10.1016/j.bbabio.2009.07.004
Cheap, Hélène ; Bernad, Sophie ; Derrien, Valérie ; Gerencsér, László ; Tandori, Julia ; de Oliveira, Pedro ; Hanson, Deborah K. ; Maróti, P. ; Sebban, Pierre. / M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria. In: BBA - Bioenergetics. 2009 ; Vol. 1787, No. 12. pp. 1505-1515.
@article{0c3da50380fb4977bdcbaad0a302892c,
title = "M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria",
abstract = "Bacterial reaction centers use light energy to couple the uptake of protons to the successive semi-reduction of two quinones, namely QA and QB. These molecules are situated symmetrically in regard to a non-heme iron atom. Four histidines and one glutamic acid, M234Glu, constitute the five ligands of this atom. By flash-induced absorption spectroscopy and delayed fluorescence we have studied in the M234EH and M234EL variants the role played by this acidic residue on the energetic balance between the two quinones as well as in proton uptake. Delayed fluorescence from the P+QA - state (P is the primary electron donor) and temperature dependence of the rate of P+QA - charge recombination that are in good agreement show that in the two RC variants, both QA - and QB - are destabilized by about the same free energy amount: respectively ∼ 100 ± 5 meV and 90 ± 5 meV for the M234EH and M234EL variants, as compared to the WT. Importantly, in the M234EH and M234EL variants we observe a collapse of the high pH band (present in the wild-type reaction center) of the proton uptake amplitudes associated with formation of QA - and QB -. This band has recently been shown to be a signature of a collective behaviour of an extended, multi-entry, proton uptake network. M234Glu seems to play a central role in the proton sponge-like system formed by the RC protein.",
keywords = "Bioenergetics, Electron transfer, Hydrogen-bond network, Photosynthesis, Proton transfer, Reaction center",
author = "H{\'e}l{\`e}ne Cheap and Sophie Bernad and Val{\'e}rie Derrien and L{\'a}szl{\'o} Gerencs{\'e}r and Julia Tandori and {de Oliveira}, Pedro and Hanson, {Deborah K.} and P. Mar{\'o}ti and Pierre Sebban",
year = "2009",
month = "12",
doi = "10.1016/j.bbabio.2009.07.004",
language = "English",
volume = "1787",
pages = "1505--1515",
journal = "Biochimica et Biophysica Acta - Bioenergetics",
issn = "0005-2728",
publisher = "Elsevier",
number = "12",

}

TY - JOUR

T1 - M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria

AU - Cheap, Hélène

AU - Bernad, Sophie

AU - Derrien, Valérie

AU - Gerencsér, László

AU - Tandori, Julia

AU - de Oliveira, Pedro

AU - Hanson, Deborah K.

AU - Maróti, P.

AU - Sebban, Pierre

PY - 2009/12

Y1 - 2009/12

N2 - Bacterial reaction centers use light energy to couple the uptake of protons to the successive semi-reduction of two quinones, namely QA and QB. These molecules are situated symmetrically in regard to a non-heme iron atom. Four histidines and one glutamic acid, M234Glu, constitute the five ligands of this atom. By flash-induced absorption spectroscopy and delayed fluorescence we have studied in the M234EH and M234EL variants the role played by this acidic residue on the energetic balance between the two quinones as well as in proton uptake. Delayed fluorescence from the P+QA - state (P is the primary electron donor) and temperature dependence of the rate of P+QA - charge recombination that are in good agreement show that in the two RC variants, both QA - and QB - are destabilized by about the same free energy amount: respectively ∼ 100 ± 5 meV and 90 ± 5 meV for the M234EH and M234EL variants, as compared to the WT. Importantly, in the M234EH and M234EL variants we observe a collapse of the high pH band (present in the wild-type reaction center) of the proton uptake amplitudes associated with formation of QA - and QB -. This band has recently been shown to be a signature of a collective behaviour of an extended, multi-entry, proton uptake network. M234Glu seems to play a central role in the proton sponge-like system formed by the RC protein.

AB - Bacterial reaction centers use light energy to couple the uptake of protons to the successive semi-reduction of two quinones, namely QA and QB. These molecules are situated symmetrically in regard to a non-heme iron atom. Four histidines and one glutamic acid, M234Glu, constitute the five ligands of this atom. By flash-induced absorption spectroscopy and delayed fluorescence we have studied in the M234EH and M234EL variants the role played by this acidic residue on the energetic balance between the two quinones as well as in proton uptake. Delayed fluorescence from the P+QA - state (P is the primary electron donor) and temperature dependence of the rate of P+QA - charge recombination that are in good agreement show that in the two RC variants, both QA - and QB - are destabilized by about the same free energy amount: respectively ∼ 100 ± 5 meV and 90 ± 5 meV for the M234EH and M234EL variants, as compared to the WT. Importantly, in the M234EH and M234EL variants we observe a collapse of the high pH band (present in the wild-type reaction center) of the proton uptake amplitudes associated with formation of QA - and QB -. This band has recently been shown to be a signature of a collective behaviour of an extended, multi-entry, proton uptake network. M234Glu seems to play a central role in the proton sponge-like system formed by the RC protein.

KW - Bioenergetics

KW - Electron transfer

KW - Hydrogen-bond network

KW - Photosynthesis

KW - Proton transfer

KW - Reaction center

UR - http://www.scopus.com/inward/record.url?scp=69249214136&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=69249214136&partnerID=8YFLogxK

U2 - 10.1016/j.bbabio.2009.07.004

DO - 10.1016/j.bbabio.2009.07.004

M3 - Article

VL - 1787

SP - 1505

EP - 1515

JO - Biochimica et Biophysica Acta - Bioenergetics

JF - Biochimica et Biophysica Acta - Bioenergetics

SN - 0005-2728

IS - 12

ER -