Format

Send to

Choose Destination
Mol Microbiol. 1996 May;20(4):785-97.

A single substitution in the putative helix-turn-helix motif of the pleiotropic activator PrfA attenuates Listeria monocytogenes virulence.

Author information

1
Unité des Interactions Bactéries-Cellules, CNRS URA 1300, Institut Pasteur, Paris, France.

Abstract

PrfA, the regulator of virulence-gene expression in the pathogenic bacterium Listeria monocytogenes, displays sequence similarity to members of the CAP-FNR family of transcriptional regulators. To test the functional significance of this similarity, we constructed and analysed substitutions of two amino acids of PrfA predicted to contact DNA, i.e. Ser-184 and Ser-183. Substitution of Ser-184 by Ala reduced DNA binding and virulence-gene activation, and attenuated the virulence in a mouse model of infection. In contrast, substitution of Ser-183 by Ala had the opposite effect in these functional assays. A 17bp DNA sequence, which includes a putative PrfA site, was shown to be sufficient for target-site recognition by PrfA and PrfA-S183A. Our results strongly support the hypothesis that PrfA is a structural and functional homologue of CAP. In addition, they establish a clear correlation between DNA binding by PrfA, virulence-gene activation, and virulence.

PMID:
8793875
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center