Format

Send to

Choose Destination
See comment in PubMed Commons below
Appl Environ Microbiol. 2009 Jun;75(12):3912-9. doi: 10.1128/AEM.01525-08. Epub 2009 Apr 17.

Phenol degradation in the strictly anaerobic iron-reducing bacterium Geobacter metallireducens GS-15.

Author information

1
Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Leipzig, Germany. kathleen.schleinitz@ufz.de

Abstract

Information on anaerobic phenol metabolism by physiological groups of bacteria other than nitrate reducers is scarce. We investigated phenol degradation in the strictly anaerobic iron-reducing deltaproteobacterium Geobacter metallireducens GS-15 using metabolite, transcriptome, proteome, and enzyme analyses. The results showed that the initial steps of phenol degradation are accomplished by phenylphosphate synthase (encoded by pps genes) and phenylphosphate carboxylase (encoded by ppc genes) as known from Thauera aromatica, but they also revealed some distinct differences. The pps-ppc gene cluster identified in the genome is functional, as shown by transcription analysis. In contrast to T. aromatica, transcription of the pps- and ppc-like genes was induced not only during growth on phenol, but also during growth on benzoate. In contrast, proteins were detected only during growth on phenol, suggesting the existence of a posttranscriptional regulation mechanism for these initial steps. Phenylphosphate synthase and phenylphosphate carboxylase activities were detected in cell extracts. The carboxylase does not catalyze an isotope exchange reaction between (14)CO(2) and 4-hydroxybenzoate, which is characteristic of the T. aromatica enzyme. Whereas the enzyme of T. aromatica is encoded by ppcABCD, the pps-ppc gene cluster of G. metallireducens contains only a ppcB homologue. Nearby, but oriented in the opposite direction, is a ppcD homologue that is transcribed during growth on phenol. Genome analysis did not reveal obvious homologues of ppcA and ppcC, leaving open the question of whether these genes are dispensable for phenylphosphate carboxylase activity in G. metallireducens or are quite different from the Thauera counterparts and located elsewhere in the genome.

PMID:
19376902
PMCID:
PMC2698347
DOI:
10.1128/AEM.01525-08
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center