Diversity of the transcriptional regulation of the pch gene cluster in two indigenous p-cresol-degradative strains of Pseudomonas fluorescens.
FEMS Microbiol Ecol
; 72(3): 464-75, 2010 Jun.
Article
en En
| MEDLINE
| ID: mdl-20370825
ABSTRACT
p-Cresol methylhydroxylase (PCMH), a key enzyme responsible for the catabolism of p-cresol via the protocatechuate ortho pathway, was used as a tool to characterize catabolic differences between phenol- and p-cresol-degrading Pseudomonas fluore-scens strains PC18 and PC24. Although both strains catabolize p-cresol using PCMH, different whole-cell kinetic parameters for this compound were revealed. Affinity for the substrate and the specific growth rate were higher in PC18, whereas maximum p-cresol tolerance was higher in PC24. In addition, PCMH of strain PC18 was induced during growth on phenol. In both strains, the pchACXF operon, which encodes p-hydroxybenzaldehyde dehydrogenase and PCMH, was sequenced. Transcriptional regulation of these operons by PchR, a putative sigma(54)-dependent regulator, was shown. Although the promoters of these operons resembled sigma(54)-controlled promoters, they differed from the consensus sequence by having T instead of C at position -12. Complementation assays confirmed that the amino acid sequence differences of the PchR regulators between the two strains studied led to different effector-binding capabilities of these proteins (1) phenol was a more efficient effector for PchR of PC18 than p-cresol, (2) phenol did not activate the regulator of PC24, and (3) both regulators responded similarly to p-cresol.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Operón
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Pseudomonas fluorescens
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Familia de Multigenes
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Oxigenasas de Función Mixta
Idioma:
En
Revista:
FEMS Microbiol Ecol
Año:
2010
Tipo del documento:
Article
País de afiliación:
Estonia
Pais de publicación:
ENGLAND
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ESCOCIA
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GB
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GREAT BRITAIN
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INGLATERRA
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REINO UNIDO
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SCOTLAND
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UK
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UNITED KINGDOM