Effect of hydrogen peroxide production and the Fenton reaction on membrane composition of Streptococcus pneumoniae

Stella Pesakhov, Rachel Benisty, Noga Sikron, Zvi Cohen, Pavel Gomelsky, Inna Khozin-Goldberg, Ron Dagan, Nurith Porat

    Research output: Contribution to journalArticlepeer-review

    49 Scopus citations


    As part of its aerobic metabolism, Streptococcus pneumoniae generates high levels of H2O2 by pyruvate oxidase (SpxB), which can be further reduced to yield the damaging hydroxyl radicals via the Fenton reaction. A universal conserved adaptation response observed among bacteria is the adjustment of the membrane fatty acids to various growth conditions. The aim of the present study was to reveal the effect of endogenous reactive oxygen species (ROS) formation on membrane composition of S. pneumoniae. Blocking carbon aerobic metabolism, by growing the bacteria at anaerobic conditions or by the truncation of the spxB gene, resulted in a significant enhancement in fatty acid unsaturation, mainly cis-vaccenic acid. Moreover, reducing the level of OH· by growing the bacteria at acidic pH, or in the presence of an OH· scavenger (salicylate), resulted in increased fatty acid unsaturation, similar to that obtained under anaerobic conditions. RT-PCR results demonstrated that this change does not originate from a change in mRNA expression level of the fatty acid synthase II genes. We suggest that endogenous ROS play an important regulatory role in membrane adaptation, allowing the survival of this anaerobic organism at aerobic environments of the host.

    Original languageEnglish
    Pages (from-to)590-597
    Number of pages8
    JournalBiochimica et Biophysica Acta - Biomembranes
    Issue number3
    StatePublished - 1 Mar 2007


    • Fatty acid
    • Fenton reaction
    • Hydrogen peroxide
    • Membrane lipid
    • Streptococcus pneumoniae

    ASJC Scopus subject areas

    • Biophysics
    • Biochemistry
    • Cell Biology


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